Transcript `amino acid pool`. - Homoeopathy Clinics In India,Homeopathy

BIOCHEMISTRY AND ITS ROLE IN DISEASE DIAGNOSIS
Dr. A. K. Dwivedi
INTRODUCTION
TO
BIOCHEMISTRY
BIOCHEMISTRY deals with
the chemical prosess taking
place in all living organisms
from smallest viruses to
bacteria to largest living
matter.
It is defined as , THE study of
chemical composition of
living matter and chemical
changes that occur in it
during life process.
HSTORY:
First intrdused by CARL
NEWBERG,a germen scientist in1903.
Concept was given by:Karl william
scheel
INCLUDES study of
Carbohydrates
Protiens,aminoacids,peptides
Lipids
Enzymes
Vitamins etc.
INTRODUCTION TO
ENZYMES
Enzymes are biological catalysts
responsible for supporting almost all of the
chemical reactions that maintain animal
homeostasis. Because of their role in
maintaining life processes, the assay and
pharmacological regulation of enzymes
have become key elements in clinical
diagnosis and therapeutics.

The macromolecular components of almost all
enzymes are composed of protein, except for a
class of RNA modifying catalysts known as
ribozymes. Ribozymes are molecules of
ribonucleic acid that catalyze reactions on the
phosphodiester bond of other RNAs.

Enzymes are found in all tissues and fluids of
the body. Intracellular enzymes catalyze the
reactions of metabolic pathways.

Plasma membrane enzymes regulate catalysis
within cells in response to extracellular
signals,

and enzymes of the circulatory system are
responsible for regulating the clotting of blood

Almost every significant life process is
dependent on enzyme activity.

Enzyme Classifications

Currently enzymes are grouped into six
functional classes by the International Union
of Biochemists (I.U.B.).
Number
Classification
Biochemical Properties
1
Oxidoreductases
Act on many chemical groupings to add or
remove hydrogen atoms.
2
Transferases
Transfer functional groups between donor
and acceptor molecules. Kinases are
specialized transferases that regulate
metabolism by transferring phosphate
from ATP to other molecules.
3
Hydrolases
Add water across a bond, hydrolyzing it.
4
Lyases
Add water, ammonia or carbon dioxide across
double bonds, or remove these elements to
produce double bonds.
5
Isomerases
Carry out many kinds of isomerization: L to D
isomerizations, mutase reactions (shifts of
chemical groups) and others.
Ligases
6
Catalyze reactions in
which two chemical
groups are joined (or
ligated) with the use of
energy from ATP.

Enzymes are also classified on the basis of
their composition. Enzymes composed wholly
of protein are known as simple enzymes in
contrast to complex enzymes, which are
composed of protein plus a relatively small
organic molecule. Complex enzymes are also
known as holoenzymes.

In this terminology the protein component is
known as the apoenzyme, while the nonprotein component is known as the coenzyme

Many prosthetic groups and coenzymes are
water-soluble derivatives of vitamins. It should
be noted that the main clinical symptoms of
dietary vitamin insufficiency generally arise
from the malfunction of enzymes, which lack
sufficient cofactors derived from vitamins to
maintain homeostasis.

Enzymes that require a metal in their
composition are known as metalloenzymes


Introduction - Enzyme Characteristics:
The basic mechanism by which enzymes catalyze chemical reactions
begins with the binding of the substrate (or substrates) to the active site on
the enzyme. The active site is the specific region of the enzyme which
combines with the substrate. The binding of the substrate to the enzyme
causes changes in the distribution of electrons in the chemical bonds of the
substrate and ultimately causes the reactions that lead to the formation of
products. The products are released from the enzyme surface to regenerate
the enzyme for another reaction cycle.



The active site has a unique geometric shape that is
complementary to the geometric shape of a substrate molecule,
similar to the fit of puzzle pieces. This means that enzymes
specifically react with only one or a very few similar
compounds.
Lock and Key Theory:
The specific action of an enzyme with a single substrate can be
explained using a Lock and Key analogy first postulated in
1894 by Emil Fischer. In this analogy, the lock is the enzyme
and the key is the substrate. Only the correctly sized key
(substrate) fits into the key hole (active site) of the lock
(enzyme).


Smaller keys, larger keys, or incorrectly positioned
teeth on keys (incorrectly shaped or sized substrate
molecules) do not fit into the lock (enzyme). Only the
correctly shaped key opens a particular lock. This is
illustrated in graphic on the left.
QUES: Using a diagram and in your own words,
describe the various lock and key theory of enzyme
action in relation to a correct and incorrect substrate.


Induced Fit Theory:
Not all experimental evidence can be
adequately explained by using the so-called
rigid enzyme model assumed by the lock and
key theory. For this reason, a modification
called the induced-fit
theory has been proposed.
The induced-fit theory assumes that the substrate play
a role in determining the final shape of the enzyme an
that the enzyme is partially flexible. This explains why
certain compounds can bind to the enzyme but do not
react because the enzyme has been distorted too muc
Other molecules may be too small to induce the prope
alignment and therefore cannot react. Only the proper
substrate is capable of inducing the
Induced Fit Theory:
Not all experimental evidence can be adequately explained by using the socalled rigid enzyme model assumed by the lock and key theory. For this reason,
a modification called the induced-fit theory has been proposed.
The induced-fit theory assumes that the substrate plays a role in determining
the final shape of the enzyme and that the enzyme is partially flexible. This
explains why certain compounds can bind to the enzyme but do not react
because the enzyme has been distorted too much. Other molecules may be too
small to induce the proper alignment and therefore cannot react. Only the
proper substrate is capable of inducing the proper alignment of the active site.
In the graphic on the left, the substrate is represented by the magenta
molecule, the enzyme protein is represented by the green and cyan colors. The
cyan colored protein is used to more sharply define the active site. The protein
chains are flexible and fit around the substrate.
Enzymes in the
Diagnosis of Pathology
The measurement of the serum levels of numerous
enzymes has been shown to be of diagnostic
significance. This is because the presence of these
enzymes in the serum indicates that tissue or
cellular damage has occurred resulting in the
release of intracellular components into the blood.
Hence, when a physician indicates that he/she is
going to assay for liver enzymes, the purpose is to
ascertain the potential for liver cell damage.
Commonly assayed enzymes are the amino
transferases: alanine transaminase, ALT (sometimes
still referred to as serum glutamate-pyruvate
aminotransferase,
SGPT)
and
aspartate
aminotransferase, AST (also referred to as serum
glutamate-oxaloacetate aminotransferase, SGOT);
lactate dehydrogenase, LDH; creatine kinase, CK (also
called creatine phosphokinase, CPK); gamma-glutamyl
transpeptidase, GGT. Other enzymes are assayed
under a variety of different clinical situations but they
will not be covered here.
The typical liver enzymes measured are AST and ALT. ALT
is particularly diagnostic of liver involvement as this
enzyme is found predominantly in hepatocytes. When
assaying for both ALT and AST the ratio of the level of
these two enzymes can also be diagnostic. Normally in
liver disease or damage that is not of viral origin the ratio
of ALT/AST is less than 1. However, with viral hepatitis the
ALT/AST ratio will be greater than 1. Measurement of AST
is useful not only for liver involvement but also for heart
disease or damage.
The level of AST elevation in the serum is directly
proportional to the number of cells involved as well as on the
time following injury that the AST assay was performed.
Following injury, levels of AST rise within 8 hours and peak
24-36 hours later. Within 3-7 days the level of AST should
return to pre-injury levels, provided a continuous insult is not
present or further injury occurs. Although measurement of
AST is not, in and of itself, diagnostic for myocardial
infarction, taken together with LDH and CK measurements
(see below) the level of AST is useful for timing of the infarct.
The measurement of LDH is especially diagnostic for myocardial
infarction because this enzyme exist in 5 closely related, but slightly
different forms (isozymes). The 5 types and their normal distribution
and levels in non-disease/injury are listed below.
LDH 1 - Found in heart and red-blood cells and is 17% - 27% of the
normal
serum
total.
LDH 2 - Found in heart and red-blood cells and is 27% - 37% of the
normal
serum
total.
LDH 3 - Found in a variety of organs and is 18% - 25% of the normal
serum
total.
LDH 4 - Found in a variety of organs and is 3% - 8% of the normal
serum
total.
LDH 5 - Found in liver and skeletal muscle and is 0% - 5% of the
normal serum total.
Following a myocardial infarct the serum levels of LDH rise
within 24-48 hours reaching a peak by 2-3 days and return to
normal in 5-10 days. Especially diagnostic is a comparison of
the LDH-1/LDH-2 ratio. Normally, this ration is less than 1. A
reversal of this ration is referred to as a "flipped LDH.".
Following an acute myocardial infart the flipped LDH ratio will
appear in 12-24 hours and is definitely present by 48 hours in
over 80% of patients. Also important is the fact that persons
suffering chest pain due to angina only will not likely have
altered LDH levels.
CPK is found primarily in heart and skeletal
muscle as well as the brain. Therefore,
measurement of serum CPK levels is a good
diagnostic for injury to these tissues. The levels of
CPK will rise within 6 hours of injury and peak by
around 18 hours. If the injury is not persistent the
level of CK returns to normal within 2-3 days.
Seminar Presentation
On
PROTEINS
BY
ANKUSH VANI
INTRODUCTION
The proteins are complex molecules built mainly
from a-amino acid linked together in chains. The
linkage between the amino acids is called peptide
bond; molecules built up from many (up to 100)
amino acids are called polypeptides. Proteins
consist of several polypeptide chains, crosslinkaged between specific amino acid units.
Chains containing 2-10 amino acids are called
peptides.
Amino Acids
The principal amino acids obtained by breakdown of proteins are:
Neutral amino acids - they contain one NH2 (basic) group and one COOH (acidic)
group which mutually neutralize each other.
Types:
Amino acids with unsubstantiated C chains:
glycine, almandine, valine, leucine, isolucine.
(ii) Hydroxyl-substituted amino acids:
serine, threonine.
(iii) Sulphur containing amino acids:
cytosine, cystine (oxidative product of cytosine), methionine.
(iv) Aromatic amino acids, derived from almandine:
phenylalanine, tyrosine,thyroxine, triiodothyro-nine
2. Acidic amino acids - amino acids with acidic side chain:
aspartic acid, asparagine, glutamic acid, glutamine.
3. Basic amino acids - amino acids with basic side chain:
arginine, lysine, histidine.
4. Imino acids - contains imino group but no amino group:
proline, hydroxyproline.
C. Digestion and absorption of proteins.
Digestion of proteins in the stomach
pepsin is the most important proteolytic enzyme of gastric
juiceOptimum pH for the activite of pepsin is 2 to 3 and it is
completely inactive at a pH above 5 . The hydrochloric acid in
the gastric juice provides the ideal pH for the activity of pepsin .
Pepsin acts on proteins and breaks them down into
proteoses , peptones and large polypestides . So , the proteins
reach the duodenum in these forms along with chyme.
Proteins
Pepsin
(Gastric Juice)
Proteoses
Peptones
Large polypeptides
Trypsin
Chymotrypsin
(Endopeptidases in
Pancreatic juice)
Dipeptides
Tripeptides
Carboxy peptidase
(Exopeptidase in
pancreatic juice
Polypeptides
Peptidases
(Succus
entericus)
Amino acids
DIGESTION OF PROTEINS IN THE SMALL INTESTINE
Most of the p[roteins are digested in the doudenum and jejunum by
the proteolytic enzymes of the pancreatic juice and succus entericus.
Pancreatic juice contains trypsin, chymotrypsin and carboxy peptidases.
Trypsin and chymotrypsin are called endopeptidases as these two enzymes
break the interior bonds of the protein molecules. Both the enzymes act on
proteoses and peptones split then into dipeptide and tripeptide molecules are
absorbed directly into the epithelial cells of the mucosa of the small intestine.
Carboxypeptidase from pancreatic juice breaks the terminal bonds of
the protein molecules. So, it is called exopeptidase. By the activity of
carboxypeptidase, the dipeptides, tripeptides and the polypeptides are
converted into amino acids.
The last digestion of the proteins is by proteolytic enzymes present in
the succus entericus. It contains dipeptidases, tripeptidases and
aminopolypeptidases. These enzymes act on large polypeptides and some of
the left over dipeptides and tripeptides and convert these proteins into the
final stage of single amino acids, which can be easily absorbed.
Pancreatic juice contains two more enzymes namely, collagenase and
elastease. Collagenase acts on collagen and elastase acts on elastic fibers.
ABSORPTION OF PROTEINS
The proteins are absorbed in the form of amino acids from small intestine.
The levoamino acids are actively absorbed by means of sodium co-transport, whereas,
the dextroamino acids are absorbed by means of facilitated diffusion.
The absorption of amino acids is faster in duodenum and jejunum and
slower in ileum.
D. Amino Acid Pool:Most of the tissue proteins (structural as well as
functional protein) are continuously undergoing
disintegration to release amino acids. The amino acids
derived from food (exogenous protein) and those derived
from the tissues break down (endogenous protein) enter
the circulation forming general ammo acid pool.
It
represents an availability of amino acid building units.
From this common amino acid pool, amino acids are taken
up by the cells, if a cell takes up as much amino acid as it
loses, it is in a state of dynamic equilibrium; if the loss is
greater, the cell degenerates; if the gain is greater, the cell
grows. The proteins of the body are in a state of dynamic
equilibrium i.e. a balance between simultaneous
breakdown and synthesis. The endogenous protein
turnover rate is about 80-100 gm/day being greatest in
intestinal mucosa, followed by kidney, liver, brain and
muscle in that order.
E. Essential Amino acids
These are the amino acids needed for replacement and
growth, but which cannot be synthesized by the body in
amounts sufficient to fulfil its normal requirements. The
rest of the amino acids are the non-essential amino acids
and can be synthesized in the body. It has been found that
the following amino acids are indispensable for human
adults under normal conditions: valine, leucine, isoleucine,
threonine, methionine, phenylalanine, tryptophan, lysine,
histidine and arginine .
F. Specific Metabolic Roles of Amino Acids
1.
2.
3.
4.
5.
Amino acids are the building units of all the tissue proteins including
the enzymes and many of the hormones.
Glycine is a fundamental building unit, and an inhibitory
transmitter in the spinal cord.
Arginine is responsible for urea formation and helps in creatine
synthesis.
Histidine is the precursor of histamine.
Phenylalanine can be irreversibly converted to tyrosine which is the
precursor for thyroxine, epinephrine, nor-epinephrine and melanin
pigment.
6.
Tryptophan is essential for the formation of 5 HT (serotonin).
7.
Methionine, cysteine and cystine are the only important source of
sulphur and are used for the forjnation of organic sulphates or
taurine.
G. Urinary Sulphates
The sulphur compounds of urine are derived mainly from the sulphur
containing amino acids (methionine, cysteine and cystine) of the dietary and
tissue proteins. The sulphur is excerted in urine in the following forms:
1. Inorganic sulphate :
Sulphur containing amino acids of the amino acid pool that are not used in
protein synthesis are completely oxidised and the sulphur as sulphate ions
(SO42~) are excreted in urine, with an equivalent amount of cations (Na+,
K+, NH4T). The normal range of urinary output is 0.3-3 gm of sulphate ions
/day.
2. Ethereal sulphate :
The urine contains small amounts of organic sulphate esters, R-OSO3H (ethereal sulphates), where R is the aromatic radicals. These
are the forms in which many phenols (oestrogen, steroids, indoles
and drugs like aspirin) are detoxicated and excreted in urine. The
conjugation of the phenol with sulphate from amino acids takes
place in the liver
3. Neutral sulphur e.g. cystine, mercaptans are found in the urine in
traces.
METABOLISM OF AMINO ACIDS
[A] Metabolism of amino acids involve the following reactions:
1. Oxidative deamination : Amino acids which are not used as such undergo 'oxidative
deamination'/ primarily in the liver. The overall reaction is the transformation of an
amino acid R.CH(NH2).COOH, to the corresponding keto acid, R.CO.COOH. This
involves an oxidation (or dehydrogenation) to give a-imino acid, followed by
hydrolysis liberating 'ammonia'.
CH3.CH(NH2) COOH + NAD
Alanine
coenzyme (H carrier)
amino acid oxidase
CH3.C(:NH)COOH + NAD.2H
α-imino acid reduced coenzyme
CH,C (:NH) COOH + H,O
CH2.CO.COOH+NH3
pyruvic acid
The ammonia thus formed is then used up in the synthesis of other
amino acids or excreted as urea
2. Transamination
It is the process in which deamination of an amino acid to
corresponding ketoacid is coupled with the simultaneous amination of
another ketoacid to an amino acid e.g.
transaminase
Alanine + ot-keto-glutaric acid
pyruvic acid + elutamic acid
(present in the circulation)
Body
protein
Diet
Inert protein
hair etc.
transamination
Urin
excretion
Amino acid pool
Amination
Deamination
Creatine
Purines
Pyrimidines
NH4+
Urea
Hormones
neurotransmitters
Amino acid metabolism
Common
mettabolic
pool
2. Transamination is 'reversible'. Thus plays an important role in
both the breakdown of amino-acids and their synthesis from nonprotein sources; for example, from ketoacids of the citric acid cycle.
3. Amination of non-nitrogenous residues
Amino-acids from the amino acid pool are continually being
broken down by deamination, and the processs of direct amination or
transamination are used to resynthesize some of these amino-acids.
Products of deamination formed at one site can be reaminated
elsewhere and so re-enter the 'amino acid pool'.
4. Ammonia
Ammonia formed by the kidney tubule cells, mainly from glutamine,
diffuses into the lumen of the tubules and act as a hydrogen ion
acceptor.
[B] Urea Formation
1. The excess of ammonia which is formed by deamination and not
used for reamination is converted into urea. Ammonia is very toxic to
cells whereas 'urea' is harmless even in very high concentrations. The
liver is the only site of urea formation, and that urea once formed is
not destroyed in the body.
2. Urea formation in the liver consists of the union of 2 moles of NH3
and one mole of CO2 with the elimination of H2O. This takes place
directly through the Krebs urea cycle in which 'non-protein' amino
acid ornithine acts as a catalyst to form citrulline (Fig. 8.4.2). This
reacts with a second mole of NH, to give arginine; the amidine group of
arginine is split off as urea by hydrolytic enzyme 'arginase', and
ornithine is regenerated to continue the cycle.
[C] Fate of non-nitrogenous residues from amino acids
The
non-nitrogenous
residues
remaining
.after
deamination enter the 'common metabolic pool' and are
either completely catabolised to CO., or are built up into
other body constituents.
In general, the essential amino acids are 'glucogenic' i.e.
they give rise to compounds that can readily be converted
to glucose; all the non-essential amino acids are 'ketogenic'
i.e. they give rise to ketone bodies.
Applied Aspect
In certain condition oxidative mechanisms of amino acid are
dearranged by the blockage at different point . This results in the
urinari excretion of intermediate metabalies –For example:1. Phenylketonuria : It is a form of idiocy in which there is an inability
to convert phenylalamine to tyrosine therefore
phenylalamine
accumulates, and phenyl-pyruvic acid (the deamination product of
phenylalanine) appears in the urine.
2. Alcaptonuria : Here, a normal metabolite from tyrosine appears in
the urine; such urine darkens considerably when alkaline is exposed to
air and may turn almost black.
[D] Significance of nitrogen containing constituents in urine
Mixed proteins contain an average of 16% of nitrogen, almost all of
which is excreted in the urine. The chief nitrogen containing waste
products in urine are: urea, creatinine, creatine, ammonium ions and
uric acid. A small amount of amino acids are also lost from the body
through the urine.
1. Urea - Urea is formed in the liver from ammonia derived from
amino-acids
(a) On a normal protein intake (the 'amino acid pool' is contributed by
the : ingested food), the urinary urea is mainly of food origin i.e.
exogenous proteins. Within limits, the urea output varies directly with
the recent protein intake. On a normal mixed diet, an adult's excretion
of urea is 15-50 gm/day (= 7-23 gm of urea nitrogen).
(ii) On a protein-free diet but adequate in energy content, the
amino acids are contributed to the 'pool' by breakdown of tissue
proteins only i.e. endogenous proteins. Amino acids from this
endogenous proteins cannot be rebuilt into the proteins from which
they come, because one or more of the required essential amino acid
needed for the protein synthesis has been utilized elsewhere; moreover,
these amino acids cannot be stored and are irreversibly broken down
producing first ammonia and then urea which appears in the urine.
Thus, the urinary urea on a 'protein-free diet' is wholly 'endogenous'
and is approximately 4 gm of urea/day.
(iii) In complete starvation tissue protein (specially muscle protein) is
broken down into amino acids on a much larger scale than in (ii)
above. Most of this is deaminated and the residues utilized for energy
purposes and to maintain the blood sugar level. Therefore, urea
excretion is on a much larger scale because tissue protein is not being
used as "fuel".
2. Creatine and creatinine
(i) Creatine occurs in greatest concentration in skeletal muscle, with
lesser amounts in heart muscle, brain and uterus. In resting muscle,
creatine exists largely as creatine phosphate (phosphocreatine), a
high energy compound. This is formed by the reaction of creatine
with ATP (reversible reaction). The energy of carbohydrate
catabolism in muscle is initially made available as ATP which reacts
with creatine to form ADP and large amounts of creatine phosphate.
During exercise, the reaction is reversible, maintaining the supply of
ATP (an immediate source of energy for muscle contraction).
(ii) Creatine is synthesized in the liver from arginine, glycine and
methio-nine. Creatine gets phosphorylated by ATP to give creatine
phosphate, some of which lost to the body by a slow, spontaneous
transformation to 'creatinine' is excreted in urine.
(iii) Creatinuria i.e. excretion of creatine in urine. Creatine is not a normal
constituent of the urine but may. appear in the following conditions:
(a) In children, creatinuria may be associated with the low storage power of
the muscles for creatine at an early age.
(b) Pregnancy - There is a continuous creatinuria during pregnancy,
which rises to a maximum of 1.5 gm/day after delivery; when it is derived from
the involuting uterus.
(c) Myopathies - Creatinuria occurs because of the low storage power of the
muscles.
(d) In any condition in which unusual breakdown of the tissues (specially
muscles) occurs, e.g. in starvation (muscles substance is broken down for enerev
purposes), diabetes mellitus, goitre and fever (from the increased metabolic rate).
(iv) Excretion of creatinine - Creatinine is formed in the body exclusively from
creatine via creatine phosphate; therefore, the
urinary output of creatinine
increases during exercise.
3. Ammonium ions (NH/)
4.
Amino acids - traces of many amino acids and small peptides are
found in normal urine; mainly they come from the breakdown of tissue
protein
(endogenous excretion).
5. Uric acid - This is the only end product from the metabolism of purines
and nucleic acids which normally appear in the urine
NUCLEIC ACID
[A] General
1. Purines
(i) The major purines found in nucleo-tides and nucleic acids are
adenine and guanine. 'Uric acid' is the final oxidation product of all
purines; intermediate oxidation products are hypoxanthine and
xanthine.
(ii) The diet contributes small amounts of 'free' purines to the body
from meat ^extract, tea, coffee and cocoa.
2.Pyrimidines –
The major pyrimidines found in nucleotides and nucleic acid are
cytosine, uracil and thymine.
Applied Aspect: GOUT
[A] Gout is characterised by:1 Excess of uric acid in the blood.
2. In normal persons 'metabolic pool' of uric acid is 0.7-1.3 gin which
increases to 2-4 gm.
3. Deposition of sodium monourate in articular and non-articular
structures, producing tophi.
4. Recurring attacks of acute arthritis. These are due to deposition of
microcrystals of monosodium urate in and around the structures of the
affected joints. The joint most commonly affected in early stages is
metatarsophalangeal joint of the great toe.
[B] Types: Primary and Secondary Gout
(i) Primary gout: Here, increased formation of uric acid occurs from
simple carbon and nitrogen compound without intermediary
incorporation into nucleic acids.
(ii) Secondary gout: There is an increased breakdown of nucleic acids
leading to an excess of the end-product, uric acid; it occurs in
polycythaemia, chronic leukaemias and pernicious anaemia.
[C] Treatment
a) Acute gout - The most effective drugs are colchicine,
phenylbutazone and indomethacin. They increase the renal excretion
of uric acid.
Chronic gout –
a) Prolonged administration of drugs which increases the excretion of
uric acid in the urine
by decreasing tubular reabsorption of uric acid e.g. 'probenecid' and
'salicylates
b) 'Allopurinol' inhibits the enzyme xanthine oxidase and thus reduces
uric acid synthesis.
Vitamin
A vitamin is an organic compound
required as a nutrient in tiny amounts by
an organism.
allowing supplementation of the dietary
intake.
History
The discovery of vitamins and their structureYear of
discovery Vitamin Source1909Vitamin A (Retinol)Cod liver
oil1912Vitamin B1 (Thiamin)Rice bran1912Vitamin C
(Ascorbic acid)Lemons1918Vitamin D (Calciferol)Cod liver
oil1920Vitamin B2 (Riboflavin)Eggs1922Vitamin E
(Tocopherol)Wheat germ oil, Cosmetic and Liver1926Vitamin
B12 (Cyanocobalamin)Liver1929Vitamin K
(Phylloquinone)Luzerne1931Vitamin B5 (Pantothenic
acid)Liver1931Vitamin B7 (Biotin)Liver1934Vitamin B6
(Pyridoxine)Rice bran1936Vitamin B3
(Niacin)Liver1941Vitamin B9 (Folic acid)Liver


In humans there are 13 vitamins: 4 fat-soluble
(A, D, E and K) and 9 water-soluble (8 B
vitamins and vitamin C).
Thiamin

PropertiesMolecular
formulaC12H17N4OS+Molar
mass265.356Melting point248-260 °C
(hydrochloride salt)

Thiamin or thiamine, also known as vitamin B1 and
aneurine hydrochloride, is the name of a family of
molecules sharing a common structural feature
responsible for its activity as a vitamin. It is one of
the B vitamins. Its most common form is a colorless
chemical compound with a chemical formula
C12H17N4OS. This form of thiamine is soluble in
water, methanol, and glycerol and practically
insoluble in acetone, ether, chloroform, and benzene.
Another form of thiamine known as TTFD has
different solubility properties and belongs to a family
of molecules often referred to as fat-soluble thiamines


History
Thiamin was first discovered in 1910 by Umetaro
Suzuki in Japan when researching how rice bran
cured patients of beriberi. He named it aberic acid
(later oryzanin). He did not determine its chemical
composition, nor that it was an amine. It was first
crystallized by Jansen and Donath in 1926 (they
named it aneurin, for antineuritic vitamin). Its
chemical composition and synthesis was finally
reported by Robert R. Williams in 1935.










Sources
Yeast
Oatmeal
Brown rice
Whole grain flour (rye or wheat)
Asparagus
Kale
Cauliflower
Potatoes
Oranges


Genetic diseases
Genetic diseases of thiamin transport are rare but
serious. Thiamin Responsive Megaloblastic Anemia
with diabetes mellitus and sensorineural deafness is
an autosomal recessive disorder caused by mutations
in the gene a high affinity thiamine transporter.
TRMA patients do not show signs of systemic
thiamin deficiency, suggesting redundancy in the
thiamin transport system. This has led to the
discovery of a second high affinity thiamin
transporter, SLC19A3.


High doses
The RDA in most countries is set at about 1.4
mg. However, tests on volunteers at daily
doses of about 50 mg have claimed an increase
in mental acuity.
Riboflavin
(Vitamin B2)

PropertiesMolecular
formulaC17H20N4O6Molar mass376.36
g/molMelting point290 °C (dec.)

Riboflavin (E101), also known as vitamin B2,
is an easily absorbed micronutrient with a key
role in maintaining health in humans and
animals. It is the central component of the
cofactors FAD and FMN, and is therefore
required by all flavoproteins. As such, vitamin
B2 is required for a wide variety of cellular
processes.


Toxicity
Riboflavin is not toxic when taken orally, as its
low solubility keeps it from being absorbed in
dangerous amounts from Although toxic doses
can be administered by injection, any excess at
nutritionally relevant doses is excreted in the
urine imparting a bright yellow color when in
large quantities.



Nutrition
Riboflavin deficiency
Riboflavin is continuously excreted in the
urine of healthy individuals, making deficiency
relatively common when dietary intake is
insufficient. However, riboflavin deficiency is
always accompanied by deficiency of other
vitamins.


Clinical Uses
Riboflavin has been used in several clinical
and therapeutic situations. For over 30 years,
riboflavin supplements have been used as part
of the phototherapy treatment of neonatal
jaundice. The light used to irradiate the infants
breaks down not only the toxin causing the
jaundice, but the naturally occurring riboflavin
within the infant's blood as well.

Deficiencies
Deficiencies of
vitamins are classified as either primary or
secondary. A primary deficiency occurs when
an organism does not get enough of the
vitamin in its food. A secondary deficiency
may be due to an underlying disorder that
prevents or limits the absorption or use of the
vitamin, due to a “lifestyle factor”, such as


Side effects and overdose
In large doses, some vitamins have
documented side effects that tend to be more
severe with a larger dosage. The likelihood of
consuming too much of any vitamin from food
is remote, but overdosing from vitamin
supplementation does occur. At high enough
dosages some vitamins cause side effects such
as nausea, diarrhea, and vomiting.
Niacin

Niacin, also known as vitamin B3, is a watersoluble vitamin which prevents the deficiency
disease pellagra. It is an organic compound with
the molecular formula C6H5NO2. It is a
derivative of pyridine, with a carboxyl group
(COOH) at the 3-position. Other forms of vitamin
B3 include the corresponding amide, nicotinamide
("niacinamide"), where the carboxyl group has
been replaced by an amide group (CONH2), as
well as more complex amides and a variety of
esters.


History
Niacin was first described by Hugo Weidel in 1873 in
his studies of nicotine. The original preparation
remains useful: the oxidation of nicotine using nitric
acid Niacin was extracted from livers by Conrad
Elvehjem who later identified the active ingredient,
then referred to as the "pellagra-preventing factor"
and the "anti-blacktongue factor." When the
biological significance of nicotinic acid was realized,
it was thought appropriate to choose a name to
dissociate it from nicotine, in order to avoid the
perception that vitamins or niacin-rich food contains
nicotine.



Toxicity
People taking pharmacological doses of niacin (1.5 6 g per day) often experience a syndrome of sideeffects that can include one or more of the following:
dermatological complaints





facial flushing and itching
dry skin
skin rashes including acanthosis nigricans
gastrointestinal complaints
dyspepsia (indigestion)

liver toxicity





fulminates hepatic failure
hyperglycemia
cardiac arrhythmias
birth defects
orthostasis
Pantothenic acid


Pantothenic acid, also called vitamin B5 (a B
vitamin), is a water-soluble vitamin required to
sustain life (essential nutrient). Pantothenic
acid is needed to form coenzyme-A (CoA),
and is critical in the metabolism and synthesis
of carbohydrates, proteins, and fats.



Sources
Daily requirement
Pantothenate in the form of pantethine is considered
to be the more active form of the vitamin in the body,
but is unstable at high temperatures or when stored
for long periods, so calcium pantothenate is the more
usual form of vitamin B5 when it is sold as a dietary
supplement. Ten mg of calcium pantothenate is
equivalent to 9.2 mg of pantothenic acid.


Absorption
Within most foods, pantothenic acid is in the
form of CoA or acyl-carrier protein (ACP). In
order for the intestinal cells to absorb this
vitamin it must be converted into free
pantothenic acid. Within the lumen of the
intestine, CoA and ACP are degraded from the
food into 4'-phosphopantetheine. .


Deficiency
Pantothenic acid deficiency is exceptionally
rare and has not been thoroughly studied. In
the few cases where deficiency has been seen
(victims of starvation and limited volunteer
trials), nearly all symptoms can be reversed
with the return of pantothenic acid.


Toxicity
Toxicity of pantothenic acid is unlikely. Large doses
of the vitamin, when ingested, have no reported side
effects and massive doses (e.g. 10 g/day) may only
yield mild intestinal distress and diarrhea at worst.
There are also no adverse reactions known following
parenteral or topical application of the vitamin.
Pyridoxine

PropertiesMolecular
formulaC8H11NO3Molar mass169.18
g/molMelting point159-162 °C

Pyridoxine is one of the compounds that can
be called vitamin B6, along with Pyridoxal and
Pyridoxamine. It differs from pyridoxamine by
the substituent at the '4' position. It is often
used as 'pyridoxine hydrochloride'


Function in the body
Pyridoxine assists in the balancing of sodium and
potassium as well as promoting red blood cell
production. It is linked to cardiovascular health by
decreasing the formation of homocysteine. It has been
suggested that Pyridoxine might help children with
learning difficulties, and may also prevent dandruff,
eczema, and psoriasis. In addition, pyridoxine can
help balance hormonal changes in women and aid in
immune system.


Medicinal uses
It is given to patients taking isoniazid to
combat the toxic side effects of the drug.
Pyridoxine is given 10-50 mg/day to patients
on INH (Isoniazid) to prevent peripheral
neuropathy and CNS effects that are associated
with the use of isoniazid.
Biotin
Biotin
Properties Molecular formulaC10H16N2O3SMola
mass244.31 g/molSolubility in waterSoluble
Biotin, also known as vitamin H or B7, has the
chemical formula C10H16N2O3S (Biotin; Coenzyme
R, Biopeiderm), is a water-soluble B-complex vitamin
which is composed of an ureido
(tetrahydroimidizalone) ring fused with a
tetrahydrothiophene ring. A valeric acid substituent is
attached to one of the carbon atoms of the
tetrahydrothiophene ring.





Sources
Dietary
Recommended Adequate Intake* for
BiotinAgeBiotin (mcg/day)Infants0–6
months57–12 months6Children1–3 years84–8
years12Males and Females9–13 years2014-18
years2519–70 years3070+
years30Pregnant<18-5030Lactating<185035Uses
Hair Problems
Cradle cap (seborrheic dermatitis)
Deficiency

Biotin deficiency is relatively rare and mild, and can be
addressed with supplementation. Such deficiency can be
caused by the excessive consumption of raw egg whites,
which contain high levels of the protein avidin, which
binds biotin strongly. Avidin is deactivated by cooking,
while the biotin remains intact.

Toxicity
Animal studies have indicated few, if any, effects
due to toxic doses of biotin. This may provide
evidence that both animals and humans may
tolerate doses of at least an order of magnitude
greater than each of their nutritional
requirements.


Vitamin
B12
"B12" redirects here. For other uses, see
B12 (disambiguation).
Vitamin B12Systematic (IUPAC) nameα-(5,6dimethylbenzimidazolyl)cobamidcyanideTherapeutic
considerationsPregnancy cat.?Legal
statusPOM(UK)Routesoral, ivVitamin B-12 is a vitamin,
one of eight B vitamins which is important for the normal
functioning of the brain and nervous system, and for the
formation of blood. It is normally involved in the
metabolism of every cell of the body, especially affecting
DNA synthesis and regulation, but also fatty acid synthesis
and energy production.

Systematic (IUPAC) nameα-(5,6dimethylbenzimidazolyl)cobamidcyanideTher
apeutic considerationsPregnancy cat.?Legal
statusPOM(UK)Routesoral, iv



Terminology
name vitamin B-12, known as vitamin B12
(commonly B12 or B-12 for short) generally refers to
all forms of the vitamin. Some medical practitioners
have suggested that its use be split into two different
categories, however.
In a broad sense B-12 still refers to a group of cobaltcontaining vitamer compounds known as cobalamins:
these include cyanocobalamin (an artifact formed as a
result of the use of cyanide in the purification
procedures), hydroxocobalamin (another medicinal
form), and finally, the two naturally occurring
cofactor forms of B-12: 5-deoxyadenosylcobalamin
(adenosylcobalamin—AdoB-12), the cofactor of
Methylmalonyl Coenzyme A mutase (MUT), and
methylcobalamin (MeB-12), the cofactor of 5methyltetrahydrofolate-homocysteine
methyltransferase (MTR).


Structure
Vitamin B-12 is a collection of cobalt and corrin
ring molecules which are defined by their
particular vitamin function in the body. All of the
substrate cobalt-corrin molecules from which B12 is made must be synthesized by bacteria.
However, after this synthesis is complete, the
body has a limited power to convert any form of
B-12 to another, by means of enzymatically
removing certain prosthetic chemical groups from
the cobalt atom.
Functions

Vitamin B-12 is normally involved in the metabolism of every
cell of the body, especially affecting the DNA synthesis and
regulation but also fatty acid synthesis and energy production.
However, many (though not all) of the effects of functions of
B-12 can be replaced by sufficient quantities of folic acid
(another B vitamin), since B-12 is used to regenerate folate in
the body. Most "B-12 deficient symptoms" are actually folate
deficient symptoms, since they include all the effects of
pernicious anemia and megaloblastosis, which are due to poor
synthesis of DNA when the body does not have a proper
supply of folic acid for the production of thymine. When
sufficient folic acid is available, all known B-12 related
deficiency syndromes normalize, save those narrowly
connected with the B-12 dependent enzymes Methylmalonyl
Coenzyme A mutase (MUT), and 5-methyltetrahydrofolatehomocysteine methyltransferase (MTR), also known as
methionine synthase;acid, MMA) and homocysteine.



Human absorption and distribution
The human physiology of vitamin B-12 is
complex, and therefore is prone to mishaps
leading to vitamin B-12 deficiency. The
vitamin as it occurs in foods enters the
digestive tract bound to proteins, known as
salivary R-binders. Stomach proteolysis of
these proteins requires an acid pH, and also
requires proper pancreatic release of
proteolytic enzymes referred to as pepsin.







Clinical symptoms
: The main syndrome of vitamin B-12 deficiency is Biermer's
disease (pernicious anemia). It is characterized by a triad of
symptoms:
Anemia with bone marrow promegaloblastosis (Megaloblastic
anemia)
Gastrointestinal symptoms
Neurological symptoms
Each of those symptoms can occur either alone or along with
others. The neurological complex, defined as myelosis
funicularis, consists of the following symptoms:
Impaired perception of deep touch, pressure and vibration,
abolishment of sense of touch, very annoying and persistent
paresthesias.
Sources


Foods
Vitamin B-12 is naturally found in meat (especially liver and
shellfish), milk and eggs. Animals, in turn, must obtain it
directly or indirectly from bacteria, and these bacteria may
inhabit a section of the gut which is posterior to the section
where B-12 is absorbed. Thus, herbivorous animals must
either obtain B-12 from bacteria in their rumens, or (if
fermenting plant material in the hindgut) by reingestion of
cecotrope fæces. Eggs are often mentioned as a good B-12
source, but they also contain a factor that blocks
absorption.Certain insects such as termites contain B-12
produced by their gut bacteria, in a manner analogous to
ruminant animals.An NIH Fact Sheet lists a variety of food
sources of vitamin B-12.
Other medical uses

Hydroxycobalamin, or hydoxocobalamin, also known
as Vitamin B-12a, is used in Europe both for vitamin
B-12 deficiency and as a treatment for cyanide
poisoning, sometimes with a large amount (5-10 g)
given intravenously, and sometimes in combination
with sodium thiosulfate.[45] The mechanism of
action is straightforward: the hydroxycobalamin
hydroxide ligand is displaced by the toxic cyanide
ion, and the resulting harmless B-12 complex is
excreted in urine.
Folic acid

Properties
Molecular
formulaC19H19N7O6Molar mass441.403
g/molAppearanceyellow-orange crystalline
powderMelting point250 °C (523 K),
decomp.Solubility in water0.0016 mg/ml (25
°C)Acidity (pKa)1st: 2.3, 2nd: 8.3



Folic acid and Folate are forms of the water-soluble
Vitamin B9. These occur naturally in food and can
also be taken as supplements. Folate gets its name
from the Latin word folium ("leaf").
History
A key observation by researcher Lucy Wills in 1931
led to the identification of folate as the nutrient
needed to prevent anemia during pregnancy. Dr.
Wills demonstrated that anemia could be reversed
with brewer's yeast. Folate was identified as the
corrective substance in brewer's yeast in the late
1930s and was extracted from spinach leaves in 1941.

Human reproduction

There are several important nutrients that serve as building
blocks of a healthy pregnancy. Two of the more well-known
nutrients for women during child bearing years are folic acid
and calcium (with Vitamin D). One nutrient that women are
not as familiar with is DHA ( docosahexaenoic acid) omega-3.
DHA is important for optimal infant brain, eye and nervous
system development, and has been shown to support a healthy
pregnancy. Folic acid is very important for all women who
may become pregnant. Adequate folate intake during the
periconceptional period, the time just before and just after a
woman becomes pregnant, helps protect against a number of
congenital malformations including neural tube defects.







Some current issues and controversies
about folate
Dietary fortification of folic acid
Heart disease
Stroke
Cancer
Memory and mental agility
Fertility
Ascorbic acid

Properties Molecular formulaC6H8O6Molar mass176.1241
g/molAppearanceWhite or light yellow solidDensity1.65
g/cm³Melting point190-192 °C, 463-465 K, 374-378 °F
(decomposes)Solubility in water33g/100mlSolubility in
ethanol2g/100mlSolubility in glycerol1g/100mlSolubility in
propylene glycol5g/100mlSolubility in diethyl ether,
chloroform, benzene, petroleum ether, oils, fats, fat
solventsinsolubleAcidity (pKa)4.17 (first), 11.6
(second)Hazards MSDSScienceLab.comLD5011.9 g/kg (oral,
rat)[
Uses


Ascorbic acid is easily oxidized and so is used
as a reductant in photographic developer
solutions (among others) and as a preservative.
Exposure to oxygen, metals, light, and heat
destroys ascorbic acid, so it must be stored in a
dark, cold, and non-metallic container.
The relevant European food additive E
numbers are:
Movement of electron pairs in deprotonation

PropertiesMolecular formulaC20H30OMolar
mass286.456 g/mol






E300 ascorbic acid,
E301 sodium ascorbate,
E302 calcium ascorbate,
E303 potassium ascorbate,
E304 fatty acid esters of ascorbic acid (i)
ascorbyl palmitate (ii) ascorbyl stearate.
It can be added to water that has been treated
with iodine to make it potable, neutralizing
the unpleasant iodine taste, and increasing the
health benefits of drinking water, although
increasing the chance of tooth decay.
Retinol

Retinol (Afaxin), the animal form of vitamin
A, is a fat-soluble vitamin important in vision
and bone growth. It belongs to the family of
chemical compounds known as retinoids.
Retinol is ingested in a precursor form; animal
sources (liver and eggs) contain retinyl esters,
whereas plants (carrots, spinach) contain provitamin A carotenoids.

Discovery

In 1913, Elmer McCollum, a biochemist at the
University of Wisconsin-Madison, and colleague
Marguerite Davis identified a fat-soluble nutrient in
butterfat and cod liver oil. Their work confirmed that
of Thomas Osborne and Lafayette Mendel, at Yale,
which suggested a fat-soluble nutrient in butterfat,
also in 1913.
Vitamin A was first synthesized in 1947 by two
Dutch chemists, David Adriaan van Dorp and Jozef
Ferdinand Arens.


Clinical use

Main article: Tretinoin
All retinoid forms of vitamin A are used in cosmetic
and medical applications applied to the skin. Retinoic
acid, termed Tretinoin in clinical usage, is used in the
treatment of acne and keratosis pilaris in a topical
cream. An isomer of tretinoin, isotretinoin is also
used orally (under the trade names Accutane and
Roaccutane), generally for severe or
recalcitrant acne.


Nutrition

Vitamin A deficiency is common in developing
countries but rarely seen in developed countries.
Approximately 250,000 to 500,000 malnourished
children in the developing world go blind each
year from a deficiency of vitamin A. Night
blindness is one of the first signs of vitamin A
deficiency. Vitamin A deficiency contributes to
blindness by making the cornea
Vitamin D
Cholecalciferol (D3)

Vitamin D is a group of fat-soluble
prohormones, the two major forms of which
are vitamin D2 (or ergocalciferol) and vitamin
D3 (or cholecalciferol).[1] The term vitamin D
also refers to metabolites and other analogues
of these substances. Vitamin D3 is produced in
skin exposed to sunlight, specifically
ultraviolet B radiation.







Forms
Several forms (vitamers) of vitamin D have been
discovered. The two major forms are vitamin D2 or
ergocalciferol, and vitamin D3 or cholecalciferol.
Vitamin D1
Vitamin D2:
Vitamin D3:
Vitamin D4
Vitamin D5
Biochemistry
Vitamin D is a prohormone, meaning that it has no
hormone activity itself, but is converted to the active
hormone 1,25-D through a tightly regulated synthesis
mechanism.



Nutrition
Only fish is naturally rich in vitamin D, so
much vitamin D intake in the industrialized
world is from fortified products including
milk, soy milk and breakfast cereals or
supplements.
The U.S. Dietary Reference Intake for
adequate intake (AI) of vitamin D for infants,
children and men and women aged 19–50 is 5
micrograms/day (200 IU/day)

Adequate intake increases to 10
micrograms/day (400 IU/day) for men and
women aged 51–70 and up to 15
micrograms/day (600 IU/day) past the age of
70. These dose rates will be too low during
winter months above 30° latitude. In the
absence of sun exposure, 1000 IU of
cholecalciferol is required daily for children.
4000 IU of vitamin D may be required for
adults absent summer UVB.




In food
Natural sources of vitamin D include:
Fish liver oils, such as cod liver oil, 1 Tbs. (15 mL)
provides 1,360 IU
Fatty fish species, such as:







Herring, 85g (3 oz) provides 1383 IU
Catfish, 85g (3 oz) provides 425 IU
Salmon, cooked, 3.5 oz provides 360 IU
Mackerel, cooked, 3.5 oz, 345 IU
Sardines, canned in oil, drained, 1.75 oz, 250 IU
Tuna, canned in oil, 3 oz, 200 IU
Eel, cooked, 3.5 oz, 200 IU

deficiency

Vitamin D deficiency can result from: inadequate
intake coupled with inadequate sunlight exposure,
disorders that limit its absorption, conditions that
impair conversion of vitamin D into active
metabolites, such as liver or kidney disorders, or,
rarely, by a number of hereditary disorders
Deficiency results in impaired bone mineralization,
and leads to bone softening diseases, rickets in
children and osteomalacia in adults, and possibly
contributes to osteoporosis
including:




Fish liver oils, such as cod liver oil, 1 Tbs. (15 mL) provides
1,360 IU
Fatty fish species, such as:
 Herring, 85g (3 oz) provides 1383 IU
 Catfish, 85g (3 oz) provides 425 IU
 Salmon, cooked, 3.5 oz provides 360 IU
 Mackerel, cooked, 3.5 oz, 345 IU
 Sardines, canned in oil, drained, 1.75 oz, 250 IU
 Tuna, canned in oil, 3 oz, 200 IU
 Eel, cooked, 3.5 oz, 200 IU



Rickets, a childhood disease characterized by
impeded growth, and deformity, of the long bones.
The earliest sign of subclinical vitamin D deficiency
is Craniotabes, abnormal softening or thinning of the
skull.[
Osteomalacia, a bone-thinning disorder that occurs
exclusively in adults and is characterized by proximal
muscle weakness and bone fragility.
Osteoporosis, a condition characterized by reduced
bone mineral density and increased bone fragility.
Tocopherol
α-Tocopherol


Tocopherol, a class of chemical compounds of
which many have vitamin E activity, describes
a series of organic compounds consisting of
various methylated phenols. Because the
vitamin activity was first identified in 1936
from a dietary fertility factor in rats, it was
given the name "tocopherol" from the Greek
words “τοκος” [birth], and “φορειν”, [to bear
or carry] meaning in sum "to carry a
pregnancy," with the ending "-ol" signifying
its status as a chemical alcohol.


Form
Vitamin E exists in eight different forms, four
tocopherols and four tocotrienols. All feature a
chromanol ring, with a hydroxyl group that can
donate a hydrogen atom to reduce free radicals and a
hydrophobic side chain which allows for penetration
into biological membranes. Both the tocopherols and
tocotrienols occur in alpha, beta, gamma and delta
forms, determined by the number of methyl groups
on the chromanol ring. Each form has slightly
different biological activity


History
During feeding experiments with rats Herbert McLean
Evans concluded in 1922 that besides vitamins B and
C, an unknown vitamin existed.Although every other
nutrition was present, the rats were not fertile. This
condition could be changed by additional feeding with
wheat germ. It took several years until 1936 when the
substance was isolated from wheat germ and the
formula C29H50O2 was determined. Evans also found
that the compound reacted like an alcohol and
concluded that one of the oxygen atoms was part of an
OH (hydroxyl) group












Sources
Wheat germ oil (215.4 mg/100 g)
Sunflower oil (55.8 mg/100 g)
Almond oil (39.2 mg/100 g)
Hazelnut (26.0 mg/100 g)
Walnut oil (20.0 mg/100 g)
Peanut oil (17.2 mg/100 g)
Olive oil (12.0 mg/100 g)
Peanut (9.0 mg/100 g)
Pollard (2.4 mg/100 g)
Corn (2.0 mg/100 g)
Asparagus (1.5 mg/100 g)


Deficiency
Vitamin E deficiency causes neurological
problems due to poor nerve conduction. These
include neuromuscular problems such as
spinocerebellar ataxia and
myopathies.Deficiency can also cause anemia,
due to oxidative damage to red blood cells.



Other uses
Controversy
"Megadoses" of Vitamin E are not recommended
by many government agencies, due to a possible
increased risk of bleeding. A 2005 meta-analysis
by Miller found that high-dosage vitamin E
supplements may increase all-cause mortality.
"High dose" vitamin E esters (>400 units/day)
were also associated with an increased risk in allcause mortality of 39 per 10,000 persons, and a
statistically significant relation existed between
dose and mortality, with increased risk at doses
exceeding 150 units per day.


During pregnancy
Recent studies into the use of both vitamin C
and the single isomer vitamin E esters as
possible help in preventing oxidative stress
leading to pre-eclampsia has failed to show
significant benefits, but did increase the rate of
babies born with a low birthweight in one
study.


Heart disease
Preliminary research has led to a widely held belief
that vitamin E may help prevent or delay coronary
heart disease, but larger controlled studies have not
shown any benefit. Many researchers advance the
belief that oxidative modification of LDL-cholesterol
(sometimes called "bad" cholesterol) promotes
blockages in coronary arteries that may lead to
atherosclerosis and heart attacks. Vitamin E may help
prevent or delay coronary heart disease by limiting
the oxidation of LDL-cholesterol.

Vitamin E also may help prevent the formation of
blood clots, which could lead to a heart attack.
Observational studies have associated lower rates of
heart disease with higher vitamin E intake. A study of
approximately 90,000 nurses suggested that the
incidence of heart disease was 30% to 40% lower
among nurses with the highest intake of vitamin E
from diet and supplements. The range of intakes from
both diet and supplements in this group was 21.6 to
1,000 IU (32 to 1,500 mg),

with the median intake being 208 IU (139 mg).
A 1994 review of 5,133 Finnish men and
women aged 30 - 69 years suggested that
increased dietary intake of vitamin E was
associated with decreased mortality (death)
from heart disease.


Cancer
Antioxidants such as vitamin E help protect
against the damaging effects of free radicals,
which may contribute to the development of
chronic diseases such as cancer. Vitamin E
also may block the formation of nitrosamines,
which are carcinogens formed in the stomach
from nitrites consumed in the diet. It also may
protect against the development of cancers by
enhancing immune function.
Vitamin K

This article is about the biomolecule known as
vitamin K. For the unrelated drug sometimes
referred as vitamin K, see ketamine. Vitamin .
Vitamin K1 (phylloquinone). Both contain a
functional naphthoquinone ring and an
aliphatic side chain. Phylloquinone has a
phytyl side chain.



Vitamin K2 (menaquinone). In menaquinone the side
chain is composed of a varying number of isoprenoid
residues.
Physiology
Vitamin K is involved in the carboxylation of certain
glutamate residues in proteins to form gammacarboxyglutamate residues (abbreviated Glaresidues). The modified residues are situated within
specific protein domains called Gla domains. Glaresidues are usually involved in binding calcium.




Blood coagulation: (prothrombin (factor II),
factors VII, IX, X, protein C, protein S and
protein Z).
At this time 14 human proteins with Gla
domains have been discovered, and they play
key roles in the regulation of three
physiological processes:
Bone metabolism: osteocalcin, also called
bone Gla-protein (BGP), and matrix gla
protein (MGP)
Vascular biology.


Role in disease
Vitamin K-deficiency may occur by disturbed
intestinal uptake (such as would occur in a bile
duct obstruction), by therapeutic or accidental
intake of vitamin K-antagonists or, very rarely,
by nutritional vitamin K-deficiency. As a
result, Gla-residues are inadequately formed
and the Gla-proteins are insufficiently active.


Discovery
In 1929, Danish scientist Henrik Dam investigated
the role of cholesterol by feeding chickens a
cholesterol-depleted diet. After several weeks, the
animals developed hemorrhages and started bleeding.
These defects could not be restored by adding
purified cholesterol to the diet. It appeared that together with the cholesterol

a second compound had been extracted from
the food, and this compound was called the
coagulation vitamin. The new vitamin received
the letter K because the initial discoveries were
reported in a German journal, in which it was
designated as Koagulationsvitamin. Edward
Adelbert Doisy of

Saint Louis University did much of the
research that led to the discovery of the
structure and chemical nature of Vitamin
K.Dam and Doisy shared the 1943 Nobel Prize
for medicine for their work on Vitamin K.
Several laboratories synthesized the compound
in 1939.
Mineral

A mineral is a naturally occurring substance
formed through geological processes that has a
characteristic chemical composition, a highly
ordered atomic structure and specific physical
properties. A rock, by comparison, is an

aggregate of minerals and need not have a
specific chemical composition. Minerals range
in composition from pure elements and simple
salts to very complex silicates with thousands
of known forms. The study of minerals is
called mineralogy.


Mineral definition and classification
To be classified as a true mineral, a substance
must be a solid and have a crystalline
structure. It must also be a naturally occurring,
homogeneous substance with a defined
chemical composition. Traditional definitions
excluded organically derived material.
However, the International Mineralogical
Association in 1995 adopted a new definition:


a mineral is an element or chemical compound
that is normally crystalline and that has been
formed as a result of geological processes.
The chemical composition may vary between
end members of a mineral system. For example
the plagioclase feldspars comprise a continuous
series from sodium-rich albite (NaAlSi3O8) to

calcium-rich anorthite (CaAl2Si2O8) with four
recognized intermediate compositions
between. Mineral-like substances that don't
strictly meet the definition are sometimes
classified as mineraloids. Other naturaloccurring substances are nonminerals.
Industrial minerals is a market term and refers
to commercially valuable mined materials (see
also Minerals and Rocks section below).
Physical properties of minerals

Classifying minerals can range from simple to
very difficult. A mineral can be identified by
several physical properties, some of them being
sufficient for full identification without
equivocation. In other cases, minerals can only
be classified by more complex chemical or Xray diffraction analysis; these methods,
however, can be costly and time-consuming.


Physical properties commonly used are:
Crystal structure and habit: See the above
discussion of crystal structure. A mineral may
show good crystal habit or form, or it may be
massive, granular or compact with only
microscopically visible crystals.



Talc
Rough diamond.
Hardness: the physical hardness of a mineral is
usually measured according to the Mohs scale.
This scale is relative and goes from 1 to 10.
Minerals with a given Mohs hardness can
scratch the surface of any mineral that has a
lower hardness than itself.











Talc Mg3Si4O10(OH)2
Gypsum CaSO4·2H2O
Calcite CaCO3
Fluorite CaF2
Apatite Ca5(PO4)3(OH,Cl,F)
Orthoclase KAlSi3O8
Quartz SiO2
Topaz Al2SiO4(OH,F)2
Corundum Al2O3
Diamond C (pure carbon)
Lustre


Color indicates the appearance of the mineral
in reflected light or transmitted light for
translucent minerals (i.e. what it looks like to
the naked eye).
Streak refers to the color of the powder a
mineral leaves after rubbing it on an unglazed
porcelain streak plate


Note that this is not always the same color as
the original mineral.
Cleavage describes the way a mineral may
split apart along various planes. In thin
sections, cleavage is visible as thin parallel
lines across a mineral.

Fracture describes how a mineral breaks when
broken contrary to its natural cleavage planes.




Chonchoidal fracture is a smooth curved fracture
with concentric ridges of the type shown by glass.
Hackley is jagged fracture with sharp edges.
Fibrous
Irregular


Chemical properties of minerals
Minerals may be classified according to
chemical composition. They are here
categorized by anion group. The list below is
in approximate order of their abundance in the
Earth's crust. The list follows the Dana
classification system.



Silicate class
quartz
The largest group of minerals by far are the
silicates (most rocks are ≥95% silicates),
which are composed largely of silicon and
oxygen, with the addition of ions such as
aluminium, magnesium, iron, and calcium.
Some important rock-forming silicates include
the feldspars, quartz, olivines, pyroxenes,
amphiboles, garnets, and micas.


Carbonate class
The carbonate minerals consist of those
minerals containing the anion (CO3)2- and
include calcite and aragonite dolomite and
siderite . Carbonates are commonly deposited
in marine settings when the shells of dead
planktonic life settle and accumulate on the sea
floor.

Carbonates are also found in evaporitic
settings and also in karst regions, where the
dissolution and reprecipitation of carbonates
leads to the formation of caves, stalactites and
stalagmites. The carbonate class also includes
the nitrate and borate minerals.


Sulfate class
Sulfates all contain the sulfate anion, SO42-. Sulfates
commonly form in evaporitic settings where highly
saline waters slowly evaporate, allowing the
formation of both sulfates and halides at the watersediment interface. Sulfates also occur in
hydrothermal vein systems as gangue minerals along
with sulfide ore minerals. Another occurrence is as
secondary oxidation products of original sulfide
minerals



Halide class
Halite
The halides are the group of minerals forming
the natural salts and include fluorite (calcium
fluoride), halite (sodium chloride), sylvite
(potassium chloride), and sal ammoniac
(ammonium chloride). Halides, like sulfates,
are commonly

found in evaporitic settings such as playa lakes
and landlocked seas such as the Dead Sea and
Great Salt Lake. The halide class includes the
fluoride, chloride, bromide and iodide
minerals.


Oxide class
Oxides are extremely important in mining
as they form many of the ores from which
valuable metals can be extracted. They also
carry the best record of changes in the
Earth's magnetic field. They commonly
occur as precipitates close to the Earth's
surface, oxidation products of other
minerals in the near surface weathering
zone, and as accessory minerals in igneous
rocks of the crust and mantle.

Common oxides include hematite (iron oxide),
magnetite (iron oxide), chromite (iron
chromium oxide), spinel (magnesium
aluminium oxide - a common component of
the mantle), ilmenite (iron titanium oxide),
rutile (titanium dioxide), and ice (hydrogen
oxide). The oxide class includes the oxide and
the hydroxide minerals.


Phosphate class
The phosphate mineral group actually includes any
mineral with a tetrahedral unit AO4 where A can be
phosphorus, antimony, arsenic or vanadium. By far
the most common phosphate is apatite which is an
important biological mineral found in teeth and bones
of many animals. The phosphate class includes the
phosphate, arsenate, vanadate, and antimonate
minerals.


Element class
The elemental group includes metals and
intermetallic elements (gold, silver, copper), semimetals and non-metals (antimony, bismuth, graphite,
sulfur). This group also includes natural alloys, such
as electrum (a natural alloy of gold and silver),
phosphides, silicides, nitrides and carbides (which are
usually only found naturally in a few rare meteorites).


Organic class
The organic mineral class includes biogenic
substances in which geological processes have been a
part of the genesis or origin of the existing
compound. Minerals of the organic class include
various oxalates, mellitates, citrates, cyanates,
acetates, formates, hydrocarbons and other
miscellaneous species. Examples include whewellite,
moolooite, mellite, fichtelite, carpathite, evenkite and
abelsonite.

Carbohydrate is generally defined as a neutral
compound made up of carbon, hydrogen and oxygen,
the last two elements remaining in the same proportion as in
water. The general formula is cn (H2 O) . But there are many
exceptions. For instance, rhamnose (C6 H12 O5 ) is a
carbohydrate in which H and O remain in a different
proportion. Also there are certain other compounds, such as
formaldehyde (HCHO), acetic acid (CH3COOH),lactic acid
(CH3CHOHCOOH), etc., which have got the same empirical
formula but are not carbohydrates. Thus chemically,
carbohydrates can be defined as the aldehyde and ketone
derivatives of higher polhydric alcohol (having more than OH
group).
Carbohydrate are classified according to the
number of simple sugar units present in
the molecules, viz.
(1)
(2)
I.
Simple carbohydrates.
Compound carbohydrates.
SIMPLE CARBOHYDRATES OR MONOSACCHARIDES
OR SIMPLE SUGARS.
They contain only one unit of simple sugar. For instance,
glucose, fructose, galactose, etc. Monosaccharide are further
subdivided in two ways.
(1)
(2)
According to the number of carbon atoms presents
in the molecules, viz., 1,2,3,4,5,6 and 7 carbon
atoms respectively.
According to the nature of the reducing group they
contain, viz.
(a) Aldoses, e.g., glucose. Here, the reducing
group is an aldehyde (-CHO) radicle.
(b) Ketoses- these contain ketone (C=O) group,
viz. fructose. The general formula of
monosaccharide is Cn(H2O)n.



They are colour crystalline compound having a taste
Chemically they are derivatives of polyhydric alcohols. The
aldoses are derived from primary alcohols and the ketoses
from secondary alcohols
Formation of esters. By virtue of the alcohol group they easily
from esters with acid, eg., acetates, benzoates , etc. Sach
esters, having great physiological importance, are those of
phosphoric acid , viz., hexose phosphates, which play an
important role in carbohydrat metabolism;
pentose phosphates, present in the nucleic acid and such others.



Reducing power By virtue of the aldehyde (_CHO) or
(C=O) group , simple sugars are powerful reducing agents.
They easily reduce alkaline copper , bismuth or silver
solutions.
Isomerism . Due to presence of asymmetric carbon atom in
the molecule , monosaccharides may remain in different
isomeric forms.
Optical rotation . Simple sugars rotate the plane of polarised
light and therefore may exist in either dextro or laevo forms.



Condensation . Simple sugars condense and from bigger carbohydrate
molecules, viz., polysaccharides.
Formation of glycosides. When replaceable hydrogen atom of a
hydroxyl group from sugar is substituted with other radicles it is
called a glycoside; that formed from glucose is a glucoside, from
galactose a galactoside and the like . A good number of glycosides
occur in leaves, roots, etc., of plants and are bitter solids, Phlorizine
(glucose + phloretin ), digitonin (galactose + xylose + digitogenin ),
indican (glucose + indoxyl )are a few examples of them .
Sugar acids , Either carbon atom one or six in a hexose molecule may
be oxidised to carboxyl group That formed from oxidation of number
one is named hexonic acid (glucose --> gluconic acid ), and from six
called uronic acid (glucose --> glucuronic acid ) . Many drugs and a
number of hormones combine with glucuronic acid in the body and
are excreted as glucuronides.




Formation of hexosamine . Replacement of hydroxyl group in hexose
sugar with amino one produces amino sugar or hexosamine, that
formed from glucose is glucosamine . They occur in some complex
polysaccharides.
Osazone formation . All reducing sugars condense with
phenylhydrazine and produces osazone compounds. The crystalline
forms of these osazone compounds are so characteristic that they can
be used for the identification of the particular sugar . However
glucose, glucosamine and fructose from similar osazones.
Ring Structures of the sugars, sugars not only remain as straight chain
compounds but may also remain in the form of rings , This ring may
include six members or five members Haworth has suggested all
sugars having six membered rings to be called pyranoses and those
forming five membered ring , furanoses.

Fermentation. Sugar , in general undergo fermentation by yeast and
other micro organisms.

(1). Trioses. Two trioses are of great physiological
importance glyceric aldehyde and dihydroxyacetone. The
corresponding phosphoric acid esters –phosphoglyceraldehyde
and dihydroxyacetone phosphate are of great physiological
value.
(2) .
Pentoses.

(a) Two different pentoses are present in two nucleic acids RNA.
Sugar ribose is present in the RNA, where as that present in DNA is
deoxyribose. In the free state both the sugars exist in the pyranose
form. In combination with nucleic acids they exist as
deoxyribofuranose and ribofuranose.

(b) Arabinose __-It is also pentose commonly found in gum arabicchiefly as l-arabopyranose.

(3). Hexoses The following hexoses are of physiological
importance.
a. Glucose . It is found in grapes, dextrorotatory and is an aldose.
Glucose is found in nature in free from , in the from of disaccharides,
in the from of polysaccharides and in combination with proteins . It
may remain both as a straight chain compound and as well as, in
various ring forms . a- and b- glucose are the isomeric forms.

The optical reaction of glucose is peculiar . As soon as dextrose is
dissolved in water it gives a specific rotation of +112 . On standing
the rotation gradually diminishes and finally remains constant at +52.5
.this phenomenon is called mutarotation. If however, dextrose be first
recrystallised from boiling pyridine, its solution in water at first gives
a rotation of +19 and not +112. This solution on standing also shows
mutarotation in which the specific rotation gradually increases and
finally becomes constant at the same value, +52.5 . This shows that
when in solution one particular variety changes into the other, until an
equilibrium mixture of the two forms is produced with a constant
rotation of +52.5 . Due to asymmetrical nature of carbon atom 1 in
ring form of glucose , it can exist in two forms. The a-glucose has a
rotation of =112 and the B-form , +19. A solution of glucose is an
equilibrium mixture between the straight chain and both a- and B-ring
forms, the percentage of B- being more than a- Glucose forms esters
with phosphoric acid.

b. Fructose
It is laevorotatory and is a ketone. Free fructose is present in honey
and nearly in all sweet fruits in combination it cane sugar and insulin.
In the human body normally it does not occur in free state and rapidly
converted into glucose in the liver and intestine. In contrast with other
sugars, fructose is soluble in hot absolute alcohol . Like glucose it also
forms phosphoric acid esters which play an important role in
carbohydrate metabolism.

c. Glucose . It does not occur free in nature. In the body it is found
as a constituent of lactose and cerebrosides . As polysaccharide it is
present in lichens, mosses, sea-weeds,etc

d. Mannose does not occur free in nature . It is found as a
constituent of certain animal proteins and converted to glucose in the
body. It is also found as a polysaccharide known as mannan specially
found in the ivorynuts.

(4) . Heptoses.
In the metabolic pathway of pentose phosphate by hexose
monophosphate shunt, a seven carbon ketosugar, sedoheptulose is
formed as an ester with phosphoric acid ,
2.Compound Carbohydrates

These are made up of from two to one thousand or more than
thousand monosaccharide units either with or without non –
carbohydrate units. Thus on hydrolysis these may give rise to
monosaccharide and non-carbohydrate units. These are
principally of two type;

(a) Simpler Compound
(b) More Complex Compound


The Simpler Compound –carbohydrate contains only a few
monosaccharide units and are crystalline, water – soluble and given
sweet taste . These simpler compounds are generally called
Oligosaccharides. Oligosaccharides on hydrolysis give rise to at least
two to ten monosaccharide units. Thus oligosaccharides are composed
of Disaccharides , Trisaccharides and Tetrasaccharides ,

More Complex Compounds -- these carbohydrates include
glycogen , cellulose, starch and also dextrin's which are composed of
ten or more monosaccharide units . These are mostly tasteless and are
amorphous solid substance , As these compounds are composed of
many monosaccharide units, these are called polysaccharide which are
composed of ten or more monosaccharide units, held together by
glycosidic linkages. Those polysaccharides are composed of
monosaccharides are called Homoglycans whereas those are made up
of two or more different types of monosaccharides are named as
hetroglycans..
Simpler Compound Carbohydrates
Oligosaccharides

(a) Disaccharides,

(b) Trisaccharides,

(c) Tetrasaccharides,
- include
Disaccharides
These can be regarded as condensation products of two monosaccharide
units with the elimination of one molecule of water. Their general
formula is C (H O)
During union the active groups become
engaged. In lactose only one aldehyde group becomes engaged and
one aldehyde group remains free. Similar is the case with maltose. But
in case sugar both the active radicles (--CHO of glucose and –CO of
fructose) become engaged. For this reason lactose and maltose can
reduce alkaline copper , form any osazone crystals and exhibit
mutarotation . Cane sugar , on the other hand, in which both the active
radicles are engaged, shows no reducing power, dos not form any
osazone nor shows any mutarotation . In nature about 16
disaccharides are present . Of these only the following three are of
physiological importance.

Lactose (milk sugar)—
composed of one molecule of glucose and one of galactose, found in
the milk of mammals.

Maltose (Malt sugar)—
composed of two glucose units , it is an intermediate product in
digestion of starch.

Sucrose (Cane sugar)—
On hydrolysis it gives rise to one molecule of glucose and one of
fructose. It is the chief form of sugar taken in diet. It is widely
distributed in many plants juices, such as sugar cane , sugar maple,
pine apple and also in sugar beets. Sucrose is dextrorotatory but on
hydrolysis the resulting mixture becomes laevorotatory owing to the
liberation of fructose. The laevo rotation of fructose is greater then the
dextro rotation of glucose. For this reason the mixture is known as
invert sugar and the enzyme which hydrolyses sucrose is also called
invertase .

Trehalose—
it is present in the haemolymph of insects as the principal sugar, also
occurs in yeast and fungi.

T
R
I
S
A

These type of oligosaccharides on hydrolysis give rise to three
monosaccharides units. These trisaccharides are:
(1) Mannotriose –
giving rise to two molecules of galactose and
one molecules of glucose on hydrolysis.

(2) Robinose-on hydrolysis gives rise to galactose and two
molecules of rhamnose.

(3) Rhamninose –
on hydrolysis gives rise to galactose and two
molecules of rhamnos.

(4) Raffinose –
onhydrolysis gives rise to fructose , glucose and
galactose .

(5) Gentianose—
on hydrolysis gives rise to fructose and two
molecules of glucose

(6) Melibiose—
On hydrolysis give rise to fructose and two
molecules of glucose. Among six trisaccharides described, the first
three are reducing and rest three are non-reducing the general formula
of trisaccharides is C (H O)
Only two tetrasaccharides are known. These are
(1) Stachyose which is composed of D—glucose, --galactose and –
fructose found in stachys tuberifera and

(2) Scorodose in the bulbs of garlic and onion,

Polysaccharides are made up of a large number of monosaccharide
units. During condensation all the active radicles become engaged, so
that they do not show any reducing power, do not produce any
osazone and are generally not sweet to taste. They are soluble in water
excepting cellulose. The molecules are large and hence, show
colloidal properties. The empirical formula of polysaccharides is (C
H O).
Polysaccharides are classified according to the nature of the
constituent units . For instance, those made up of pentose units are
called pentosans, those of hexose units hexosans,etc. More
specifically they are composed. For instance, glucosans are made of
glucose, galactans of galactos, fructosans of fructose and such other.

Starch, glycogen and cellulose are glucosans. Inulin is a fructosan.
Agar agar is a galactosan Gums are mixtures of both pentosans and
hexosans.

Starch.—
This is the chief form of carbohydrate taken in diet. It is
manufactured by the plants and plays the same role in them as
glycogen dose in animals, I.e., an easily available sugar store. It is the
main constituent of food grains. Starch form different sources can be
identified form their microscopic peculiarities . It is insoluble in cold
Water due to the presence of an outer cellulose layer around the
granule. On boiling the insoluble cellulose covering ruptures and
starch enters into a colloidal solution. It is a glucosen and on
hydrolysis breaks down into glucose. It gives blue colour with iodine .
It has got no reducing power and is tasteless. Starch is a mixture of
two substance having similar structure – amylose (mol wt 60.000)
And amylopectin (mol. Wt.300.000) both being composed of chains of
24 to30 glucopyranose units.

Glycogen. –
it is called animal starch ; because it is in this form
that glucose remains stored in the liver and muscles of animal body.
Glycogen is also found in those plants which do not possess any
chlorophyll, such as yeast, fungi, etc., but not in green plants. There is
probably more than one type of glycogen. When rabbit is fed with
glucose , it synthesises a glycogen containing 12 glucose units, but if
fed with galactose it forms a glycogen with 18 glucose units , but
curiously enough , mixtures of glycogens with 12 and 18 units .are not
found. Glycogen is soluble in water, makes an opalescent solution and
gives reddish colour with iodine. The glycogen molecule contains
many glucose units. The units are joined by linkage between carbon 1
of one unit to carbon 4 of the next one; branches involving 1,6
linkages are frequently present.

(c) Dextrins—
They do not occur naturally, but are the split
products of starch resulting form hydrolysis For this reason they ought
to have been described as derived carbohydrates. The term dextrin is a
group name including several varieties of dextrins. The earlier
products of hydrolysis of starch all called dextrins the name of the
different dextrins are given according to their colour reaction with
iodine. The first dextrin formed is amylodextrin giving blue colour
with iodine, the next product is called erythrodextrin giving red colour
with iodine and the next product gives no colour with iodine and is
called achroodextrin. As these products become smaller and smaller,
they develop more and more the characteristic properties of
monosaccharide, such as the reducing power, a sweet taste and the
others.

(d) Cellulose.—
it is a stable, insoluble compound, found in the
plants and never present in the animal body. Cellulose is taken with
vegetable food. It can not be digested by the human beings .
Herbivorous animals can digest cellulose with the help of bacteria.
Although indigestible, yet cellulose is of considerable importance in
human dietetics, because it add ‘bulk’ to the intestinal contents,
stimulate peristalsis and there by help in the formation and evacuation
of faeces. Filter papers, commonly used in the laboratories, are almost
pure cellulose .

(e) Inulin. –
It is a polysaccharide composed of D-fructose units. It
is a white crystalline powder and is readily soluble in hot water. It
dose not give any such characteristic colour with iodine.

Other polysaccharides containing carbohydrate and noncarbohydrate units are:

(1) Heteropentosans

(2) Heterohexosans
(3) Mucopolysaccharides– are composed of two to six different

monosaccharides units including amino sugar and uronic acid. Many
important biological compounds are included in this group, they are
hyaluronic acid chondroitin sulphate, heparin, blood group substances,
etc. the first three are called acid mucopolysaccharides due to their
acidic character. The mucopolysaccharides in tissues are usually
present in combination with protein and are called glycoproteins .




(a) It is the readily available fuel of the body .
(b) It also constitutes the structural material of the organism.
(c) It also acts as important storage of food material of the
organism.
(d) Carbohydrate also plays as a key role in the metabolism
of amino acids and fatty acids.