Transcript Karbohidratlar - mustafaaltinisik.org.uk

Willmore 2003
Carbohydrates
a) Solar energy
photosynthesis
Carbohydrates
Other organic compounds
b) Definition : Carbohydrates contain carbon, hydrogen, and oxygen which can directly,
or indirectly after hydrolysis, reduce alkali solutions of heavy metal salts.
They are generally known as POLYHYDROXYALDEHYDES or KETONES
and can yield aldehydes or ketones upon hydrolysis.
Carbohydrate = “hydrated carbons”. The general formula is : Cm(H2O)n
c) Types :
1) MONOSACCHARIDES 2C
9C
: the simplest of carbohydrates in that they cannot yield smaller molecules
upon hydrolysis
2) OLIGOSACCHARIDES 2
10 monosaccharides units
: joined by GLYCOSIDIC LINK
: oligosaccharides, upon hydrolysis, will yield constituent monosaccharides
3) POLYSACCHARIDES > 10 monosaccharide units joined by glycosidic links
: oligosaccharides, upon hydrolysis, will yield constituent monosaccharides
4) HOMOPOLYSACCHARIDES contain the same monosaccharide units
5) HETEROPOLYSACCHARIDES contain different monosaccharide units
Carbohydrates
d) BIOCHEMICAL IMPORTANCE
1) Energy provision and storage
2) Structure and protection
3) Conversion to other compounds eg. Carbohydrates
4) Internal units of other compounds
eg. Ribose in RNA
NAD
etc.
Fat
Monosaccharides
ALDOSES : Contain Aldehyde groupings
KETOSES : Contain Ketone groupings
( ose = sugar )
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Carbohydrates
TRIOSES
KETOSES
ALDOSES
H
: D-glyceraldehyde
(OH on right hand side)
: D- SERIES SUGARS
: predominent sugars in
nature are in the D- series
: L- series sugars can not
be used
CH2OH
(1)
C O
H * C OH
CH2OH
C O
(2)
CH2OH
*n-1
simplest
A sugar with 3 carbon atoms is known as TRIOSE (aldehyde, ketone)
TETROSES
H
C
Aldose form
D- ERYTHROSE
Aldose sugar
in D series
O
H *C OH
H
*C
OH
CH2OH
* chiral center
Ketose form
D- ERYTHROLOSE
Ketone sugar
in D-series
CH2OH
C O
H *C OH
CH2OH
* only one chiral center
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Carbohydrates
PENTOSES (5 C)
ALDOSES 4 D-SERIES MEMBERS
KETOSES 2 D- SERIES MEMBERS
HEXOSES (6 C)
ALDOSES 8 D- SERIES MEMBERS
KETOSES 4 D-SERIES MEMBERS
RING STRUCTURES (cyclic form)
C
C
C
- carbon chain
tends to bend
back upon
O
itself
- =O and -OH
OH
5
brought together
C
to favour
HEMIACETAL
FORMATION
1
C
HEMIACETAL
Hemiacetal is a condensation of aldehyde
C
C
O
O
OH
C
C
C
C
PYRANE
C
*C
C
C
PYRANOSE
* chiral
center
H
C
O
and hydroxy (-OH) groups.
HEMIACETAL FORMATION
PYRANOSE : contains 5 carbons and 1 oxygen.
Aldose form : The oxygen is placed between the carbons at the position C1
and C5.
Ketose form : The oxygen is placed between the carbons at the position C2
and C6.
FURANOSE : contains 4 carbons and 1 oxygen.
Aldose form : The oxygen is placed between the carbons at the position C1 and C4.
Ketose form : The oxygen is placed between the carbons at the position C2 and C5.
3
C
2
2
1 CH2OH
1
4C 3
3C
O
4
C
5
1 CH2OH
C
5
C
6
PYRANOSE
2
3
4C
2C
1
O
4
C
5
FURANOSE
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HEMIACETAL FORMATION
As a consequence of ring structure we have a chiral center.
If OH is projecting downwards
α anomer
If OH is projecting upwards
β anomer
O
O
OH
OH
OH
b
a
O
O
OH
a
b
f) REACTIVITY
1) Potential reducing group
aldehyde
grouping
O OH
H
O
aC
C
O
aC
OH
a anomer
straight
chain
form
b anomer
: an unreacted OH group at C1 of aldose and C2 of ketose
: an unreacted OH group is a potential reducing group, forming a straight-chain
molecule with an aldehyde grouping on the end
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HEMIACETAL FORMATION
2) High capacity to rotate plane polarized light (POLARIMETER)
- Translated in to sugar units.
3) Separation by CHROMATOGRAPHY
- HPLC
- Gas chromatography (use of derivatives)
4) High capacity to interact with water
- Hydrophilic
Naturally Occurring Monosaccharides
TRIOSES
D-GLYCERALDEHYDE-3-PHOSPHATE
DIHYDROXYACETONE PHOSPHATE
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PENTOSES
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HOH2C
O
OH
OH
OH
( RNA, NAD, Co Acet )
OH
H
b-D-DEOXYRIBOFURANOSE
( DNA )
CH2OH
CH2OH
O
a)
O
OH
b-D-RIBOFURANOSE
HEXOSES
HOH2 C
O
b)
HOH
OH OH
OH
D-GLUCOPYRANOSE
(D-GLUCOSE)
HOH
OH OH
OH
D- MANOSE
D-GLUCOPYRANOSE is the most abundant
monosaccharide in nature. We can find the free
form in animal blood. It feeds the brain and is found
in plant sap. The combined form is: Oligosaccharides
: Polysaccharides.
D-MANOSE is a naturally
occuring aldose.
The combined form is
: Polysaccharides
: Mucopolysaccharides
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CH2OH
c)
d)
O
OH
HOH2C
HOH
O
5
OH
OH
D-GALACTOSE
Combined form in Oligosaccharides
and Polysaccharides.
CH2OH
2
OH OH
aanomer
OH
KETOHEXOSES (D-FRUCTOSE)
In free form it occurs as Pyranose, but in
combined form it occurs as Furanose.
In the a-anomer, the OH hangs down
(involved in cyclic form of sugar).
Ring structures have to involve aldehyde or ketone groupings.
Fructose : in free form is sweet
: component of foetal animal blood
: component of photosynthetic plant sap
: present in seminal fluid (provides energy for sperm)
: basic building blocks of oligo and polysaccharides
MONOSACCHARIDES DERIVATIVES
: modification of structure
1) AMINO SUGARS
Frequently NH2 (basic)
occurs as:
CH2OH
O
O
HOH
NH
C
CH3 (neutral)
(N acetyl grouping). This
removes the basicity of NH2 .
OH OH
NH2
2-AMINO-D-GLUCOSE = D- GLUCOSAMINE
D- GALACTOSAMINE
D- MANNOSAMINE
: these amino sugars give us MUCOPOLYSACCHARIDES (components by definition)
: associated with structure and protection of cells
: they are also occasionally acylated
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MONOSACCHARIDES DERIVATIVES
2) SUGAR ACIDS
COH
COH
COOH
[o]
[o]
readily
oxidized
readily
oxidized
COOH
CH2OH
CH2OH
URONIC ACID
FAMILY
ALDONIC ACID
FAMILY
COO
D-GLUCURONIC ACID
D-GALACTURONIC ACID
D-MANNURONIC ACID
-
COOH
O
HOH
OH
SH
OH
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MONOSACCHARIDE FAMILY
ALDOSES
TRIOSES (3c)
Asymmetric C=1
H
H
C O
C O
HO C H
H C OH
CH2OH
CH2OH
21 = 2 isomers
D-GLYCERALDEHYDE
TETROSES (4c)
Asymmetric
C=2
22 = 4 isomers
L-GLYCERALDEHYDE
H
H
C O
C O
HO C H
H C OH
H C OH
H C OH
CH2OH
CH2OH
21 = 2D series isomers
D-THREOSE
D-ERYTHROSE
PENTOSES (5c)
H
H
H
H
C O
C O
C O
C O
H C OH
HO C H
H C OH
23 = 8 isomers
H C OH
H C OH
22 = 4D series isomers
H C OH
H C OH
H C OH
CH2OH
CH2OH
CH2OH
D-RIBOSE
HEXOSES (6c)
24 = 16 isomers
23
= 8D series isomers
D-ARABINOSE
HO C H
HO C H
HO C H
D-XYLOSE
H C OH
CH2OH
D-LYXOSE
H
H
H
H
H
H
H
H
C O
C O
C O
C O
C O
C O
C O
C O
H C OH HO C H
H C OH HO C H
H C OH
HO C H
H C OH
HO C H
H C OH
HO C H
H C OH
H C OH HO C H
H C OH
H C OH
H C OH
H C OH HO C H
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
CH2OH
D-ALLOSE
D-ALTROSE
D-GLUCOSE
H C OH
HO C H
HO C H
HO C OH
HO C H
HO C H
D-MANNOSE D-GULOSE
D-IDOSE
D-GALACTOSE
D-TALOSE
MONOSACCHARIDE FAMILY
KETOSES
CH2OH
Asymmetric C=0
C O
20 = 1 compound
CH2OH
DIHYDROXYACETONE
CH2OH
C O
Asymmetric
C=1
H C OH
CH2OH
21 = 2 isomers
20 =1D series COMPOUND
D-ERYTHRULOSE
CH2OH
CH2OH
C O
C O
H C OH
22 = 4 isomers
HO C H
H C OH
H C OH
CH2OH
CH2OH
21 = 2 D series isomers
D-RIBULOSE
23 = 8 isomers
22 = 4 D series isomers
D-XYLULOSE
CH2OH
CH2OH
CH2OH
CH2OH
C O
C O
C O
C O
H C OH
HO C H
H C OH
HO C H
H C OH
H C OH
H C OH
H C OH
H C OH
H C OH
CH2OH
CH2OH
CH2OH
CH2OH
D-ALLULOSE
D-FRUCTOSE
D-SORBOSE
HO C H
HO C H
D-TAGATOSE
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MONOSACCHARIDES
Detoxication
Detoxication makes sugar acids more water soluble so they can be excreted
(eg. ASPIRIN derivative of D-glucuronic acid).
In combined form, these turn up in various polysaccharides.
Can vary the behaviour of carbohydrates by potential basic group (negative group)
on uronic acid.
Monosaccharides : are joined via glycosidic link.
METHYL a- D-GLUCOSIDE
OLIGOSACCHARIDES
a type of glycoside
CH2OH
CH2OH
O
O
ethanol
+
HO
H3C
OH
OH
OH
OH
OH
OCH3
OH
H2O
OH
: a and b exist in equilibrium
: if starting off with the b form  METHYL-b-D-GLUCOSIDE
: there would be a potential for two entirely different compounds
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OLIGOSACCHARIDES
1) a-GLUCOSIDE : is easily hydrolyzed
: succeptible to attack by a-GLUCOSIDASE enzyme
CH2OH
O
H
H
OH
H
OH
O
H
2) b-GLUCOSIDE
: is less easily hydrolyzed
: also attacked by b-GLUCOSIDASE enzyme
H
OH
CH2OH
O
H
O
H
OH
OH
a-GLYCOSIDIC LINKS
: polysaccharides involved in energy production
: is easily hydrolyzed and can be attacked by an enzyme
H
H
H
OH
b-GLYCOSIDIC LINKS
: is extremly hard to hydrolyze and very stable
: has biological importance in structure and protective compounds
: OH group can be provided by another sugar (naturally occurring
disaccharides)
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NATURALLY OCCURING DISACCHARIDES
1)
CH2OH
CH2OH
O
1
OH
OH
O
OH
FULL ACETAL (not hemi)
O
4
OH
OH
a-GLYCOSIDIC LINK
H2O Maltose
: a naturally occuring disaccharide
: a degradation product of starch
: easily hydrolyzed
MALTOSE
Maltose is the same as Methanol except that it uses OH on the second sugar group.
As soon as this occurs the ring structure cannot be opened.
CH2OH
CH2OH
2)
potential reducing
group (it can react
with heavy metals)
O
O
O
OH
HOH
OH
OH
OH
b- GLYCOSIDIC LINK
OH
CELLOBIOSE
Cellobiose
: a degradation product of
cellulose
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3)
O
O
OH
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CH2OH
CH2OH
O
OH
HOH
OH
Lactose
D - GLUCOSE
D - GALACTOSE
OH
OH
b- GLYCOSIDIC LINK
Lactose is a milk sugar (5% composition of milk). It provides energy for infants.
Lactose intolerance is the lack of enzyme that helps to digest lactose.
CH2OH
O
a-D- GLUCOSE
4)
*
OH OH
OH
O
HOH2C
O
OH
OH
* : no unreacted OH grouping
: locked tight shut
: no potential reducing group
: NON-REDUCING SUGAR
: it does not have the
capacity to reduce
heavy metals or salts
Sucrose
: sweetener
b- D- FRUCTOSE : plant product
: commercial - sugar cane
- sugar beet
5) TREHALOSE : a non reducing sugar
: in insects
: contains 2 glucose molecules
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POLYSACCHARIDES
GENERAL
a) most abundant type of carbohydrate
b) classification 1) ENERGY - a-glycosidic link
2) STRUCTURE AND PROTECTION - b-glycosidic link
ENERGY POLYSACCHARIDES
GENERAL - why are these used by the cell?
1) Large molecular weight - large mass
1) large aggregates of small MW compounds vrs.
2) colloid state found with larger molecules
2) Protection of cell’s colligative properties
- the properties of solution are dependent upon the # particles
- larger molecules are easier to store (carry around) and also protect against
water loss
- water balance - osmotic properties of a cell depend upon the number
of particles in solution and not the mass of those particles
- 1 gram of polysaccharide has the same osmotic properties as a milligram
of individual glucose units
POLYSACCHARIDES
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3) PLANT STARCH
a) Occurs as granules in cell cytoplasm (30 - 100 nm chains).
b) They are heterogenous (molecular similarity). Plant starch is composed of
1 part AMYLOSE and 3 parts AMYLOPECTINE.
c) Plant starch composes 60% of our daily caloric intake.
AMYLOSE : composed of D- glucose units joined in 1-4 a glycosidic links
: polymers of maltose
: molecular weight is 60,000 to 1,500,000 daltons
AMYLOPECTINE
25 units
: structure is not linear
: branched (tree-like) with chains of D-glucose units joined
in a 1-4 a-glycosidic link
: branch points of 1-6 a-glycosidic link (anomeric C atom
(aldose and ketose C)) - always involves C1
: branching provided by OH on C6
: 25 units per chain
: compacts the space taken by many glucose units into a
smaller volume
POLYSACCHARIDES
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4) GLYCOGEN
: animal product and is present in muscle and liver
: muscle is a primative sort of tissue with primative energy derivation
: it has very large molecular weight (millions)
: it's structure is similar to amylopectine except that it is more highly branched
: the molecules in glycogen are more compact and it has 1 to 6 a-glycosidic
links
: every 8 to 10 units is a D-glycose unit
5) DEXTRANS
: form of energy storage in bacteria
: it is composed of D-glucose joined via various glycosidic links
STRUCTURAL POLYSACCHARIDES
CELLULOSE
: the most abundant natural product and 50 % of all natural organic material in
biosphere contain cellulose
: has linear chains of D-GLUCOSE units joined via 1-4 b-glycosidic links
: the polymer of CELLOBIOSE
: has the same chemical component of amylose and is involved in structure and
rigidity of plant cells (H-bonding between chains)
: not utilized by mammals except the ruminants (ruminants possess symbiotic
microorganisms in lumen)
: cellulose provides an easy and cheap way to feed cattle
MUCOPOLYSACCHARIDES
a) Generally occur in association with proteins
GLYCOPROTEINS < 4% hexosamine (amino sugars)
MUCOPROTEINS > 4% hexosamine
b) Chitin (no protein)
: N-ACETYL-D-GLUCOSAMINE
: units joined via1-4 b-glycosidic link
: compare to structure of cellulose
: exoskeletons of insects and crustaceans
: important in pesticide development
c) Mucopolysaccharides have a wide range of activities
: Hyaluronic acid, D-Glucuronic acid, N-Acetyl-D-Glucosamine
: joined by 1,3 b- and 1,4 b-glycosidic links
: found in cell coat
: joint lubricants
: blood group factors and blood typing
: reflects in surface of red blood cell
: an anticoagulant (heparine) is a mucopolysaccharide
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POLYSACCHARIDE DEGRADATION
General
a) polysaccharides undergoes degradation to permit use of constituent monosaccharides
(plant starch, glycogen)
b) Pathway of degradation varies with cellular location.
Release of monosaccharides
1) Extracellular (outside of the cell) hydrolysis eg. D-GLUCOSE
: gastrointestinal tract - still considered outside of the body
- cells secrete enzymes to outer body that
conduct hydrolysis
: salivary amylase and pancreatic amylase
- catalyze the hydrolysis of 1-4 a-glycosidic links
- amylo-1,6-a-glucosidase - hydrolysis of any branch
points (1-6 a)
- introduction of water
- important to digestion (broken down before being absorbed)
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Release of monosaccharides
2) Intracellular phosphorolysis
- bond cleavage with phosphoric acid (uses elements of phosphate)
O
-O
CH 2OH
O
OH
P
O
-
CH 2OH
CH 2OH
O
O
O
OH
OH
OH
=
OH
O
OH
slight
OH
OPO3
OH
OH
D- Glucose-1-phosphate
- working from non-reducing end of molecule
- nucleophilic attack of phosphate on C1
- chopping off at non reducing end (branching points are obstacles)
- phosphorilytic degradation of glycogen results in release of D-glucose-1-phosphate
- controlled by consumption of the product
- enzyme  phosphorylase regulated and this system is crutial in deriving energies from
energy bank
- 2 forms of phosphorylases: a and b
balance
Phosphorylase a (active)
Phosphorylase b (inactive)
2 Pi
- bond breaking, covalent modification
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Phosphorylase phosphatase:
: conversion between active and inactive forms
: inactive form is in muscle
: if using phosphate group from ATP  ADP and AMP accumulate (trouble)
: AMP positively modifies system (changes shape of the phosphatase to make it active)
: take AMP and use it as an allosteric modifier to convert to an active form
: ATP (negative) and AMP (positive) compete for allosteric sites
always
operational
2 Pi
(+) AMP
(-) ATP
Phosphorylase a active
Phosphorylase b inactive
Phosphorylase phosphatase
allosteric
modification
covalent
modification
Phosphorylase
phosphotase
kinase
cleaves off Pi
2 ATP
2 ADP
What turns phosphorylase kinase on?
: hormones: ADRENALIN in muscle, GLUCAGON in liver
: stimulate the release : ATP upon hormone stimulation releases 2 pyrophosphate
: cAMP stimulates the enzyme system and turns the protein kinase inactive to a protein
kinase active. The active protein kinase stimulates the phosphorylase kinase.
: release of glucose from glycogens creates instant release of energy
Phosphorylase phosphatase:
cAMP
intracellular messenger
ATP
Protein Kinase (inactive)
adenylate cyclase
forms
upon hormonal
stimulation
covalent
modification
cAMP
AMP + PP (= pyrophosphate)
Protein Kinase (active)
stimulates
Phosphorylase Kinase
: cAMP stimulates the enzyme system and turns the protein kinase inactive to a protein
kinase active
: the active protein kinase stimulates the phosphorylase kinase
: How does the system know when to shut down?
- by consuming cAMP
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CARBOHYDRATES
1. Structural formulae (eg. D-Glucose)
CH 2OH
CHO
H
C
OH
HO
C
H
O
CHO
H
OH
H
H
OH
CH 2OH
HO
O
HO
H
C
OH
OH
H
C
OH
OH
CH 2OH
CH 2OH
H
OH
H
H
H
OH
HO
H
OH
OH
H
H
OH
( Fischer formula)
(Chair formula)
(Haworth formula)
D-Glucose
b - D-Glucopyranose
2. Biologically important monosaccharides
H
O
O
O
HOCH2
HOCH2
H
H
H
H
H
O
OH HOCH2
OH
H
H
H
OH
HO
H
H
H
CH 2OH
OH
HO
H
CH 2OH
OH
HO
OH
HO
b -D-2-Deoxyribofuranose
bD-Ribofuranose
OH
H
OH
H
b -D-Fructofuranose
O
OH
H
H
OH
b D-Glucopyranose
H
H
H
OH
OH
HO
H
OH
H
OH
b -D-Fructopyranose
CH 2OH
H
OH
H
HO
O
O
H
OH
H
CH 2OH
CH 2OH
H
HO
H
H
H
OH
b -D-Galactopyranose
H
H
H
bD-Mannopyranose
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3. BIOLOGICALLY IMPORTANT DISACCHARIDES
CH2 OH
CH2 OH
CH2 OH
H
H
O
O
H
H
H
H
H
H
OH
H OH
O
H
H
OH
OH
H
H
H
H OH
O
OH
CH2
O
O
OH
OH
H
H
OH
OH
OH
H
OH
H
OH
H
ISOMALTOSE
MALTOSE
(4-O-a-D-GLUCOPYRANOSYL-D-GLUCOPYRANOSE)
(6-O-a-D-GLUCOPYRANOSYL-D-GLUCOPYRANOSE)
CH2 OH
CH2 OH
O
H
CH2 OH
H
O
O
OH
H
CH2 OH
H
O
H
O
H
OH
O
H OH
H
H
OH
OH
OH
H
H
OH
OH
H OH
H
H
H
H
H
OH
OH
CELLOBIOSE
LACTOSE
(4-O-b-D-GLUCOPYRANOSYL-D-GLUCOPYRANOSE)
(4-O-b-D-GALACTOPYRANOSYL-D-GLUCOPYRANOSE)
CH2 OH
CH2 OH
O
O
H
OH
H
H
H
H
OH
H
OH
H
H
OH
OH
H
H
OH
OH
O
CH2 OH
O
O
HOH2C
O
H
H
H
H
OH
OH
H
H
OH
TREHALOSE
(a-D-GLUCOPYRANOSYL-a-D-GLUCOPYRANOSIDE)
H
OH
OH
H
CH2 OH
SUCROSE
(a-D-GLUCOPYRANOSYL-b-D-FRUCTOFURANOSIDE)
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Study sheet- key words
1. Aldoses
2. ketoses
3. D- sugars
4. No. of stereoisomers
5. Reducing sugars
6. Mutarotation
7. Hemiacetals
8. Anomers ( a and b)
9. Pyranoses
10. Furanoses
11. Glycosides (acetals)
12. D- Glucopyranose
13. D- Galactopyranose
14. D- Glucuronic acid
15. D- Galacturonic acid
16. D- Glucosamine
17. D- Galactosamine
18. Maltose
19. Isomaltose
20. Cellobiose
22. Lactose
23. Storage Polysaccharides
24. glycogen
25. Starch
26. Amylose
27. Amylopectine
28. Dextran
29. Structural Polysaccharides
30. Cellulose
31. Chitin
32. Mucopolysaccharides
33. Glycogenolysis
34. Glycolysis
35. Control Sites
36. ATP Requirements
37. ATP Production
38. Anaerobic Glycolysis (all steps)
39. Lactate
40. Ethanol
41. Aerobic ATP Formation from
glycolysis
21. Sucrose
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