Transcript Vitamins in metabolism

Vitamins
and Vitamin-Like Substances
•Names and roles - vitamins
•Names and roles - vitamin-like
•Deficiencies and sources -vitamins
•Deficiencies and sources - vitamin-like
•Role in pathways
•Neurotransmitter overview
•Neurotransmitter pathway
•Tetrahydrofolate conversions
•Tetrahydrofolate examples
•B12 pathways
Eric Niederhoffer
SIU-SOM
Names and Roles
Vitamins
A
retinol
phototransduction
B1 thiamine
carbohydrate metabolism
B2 riboflavin
redox, respiration
B3 niacin
redox
B5 Pantothenic acid
B6
tca, fa and cholesterol
pyridoxine
pyridoxamine
pyridoxal
aa metabolism
glycogenolysis
B7 Biotin
gluconeogenesis, tca, fa, aa
B9 Folic acid
1C metabolism
B12 cobalamin
1C&H metabolism
C
ascorbic acid
hydroxylation
D
cholecalciferol
bone remodeling
E
tocopherols
antioxidant
K
phytylmenaquinone
multiprenylmenaquinone
coagulation
bone remodeling
Names and Roles
Vitamin-Like Substances
Choline
ac, pl
Carnitine
fa acyl group transfer
Bioflavonoids
antioxidants
Lipoic acid
tca acyl group transfer
Coenzyme Q
electron transport
Inositol
phospholipids
p-Aminobenzoic acid
folate component
Deficiencies and Sources
Vitamins
preformed: liver, egg yolk, butter, milk
b-carotene: dark green and yellow veggies
A - night blindness
B1 - beri-beri
B2 - pellagra
seeds, nuts, wheatgerms, legumes, lean meat
B3 - pellagra
meats, nuts, legumes
meats, nuts, legumes
B5 - none known
yeast, grains, egg yolk, liver
yeast, liver, wheatgerm, nuts, beans,
bananas
corn, soy, egg yolk, liver, kidney,
tomatoes
B6 - neurologic disease
B7 - widespread injury
B9 - anemia
yeast, liver, leafy veggies
B12 - pernicious anemia
liver, kidney, egg, cheese
C - scurvy
citrus and soft fruits
D - ricketts, osteomalacia
E - neurologic?, hemolytic anemia
K - bleeding disorders
milk, fortified food, fish oils,
egg yolks, liver
veggie oils, nuts
green leafy veggies, fruits, dairy products,
veggie oils, cereals, meats
Deficiencies and Sources
Vitamins-Like Substances
Choline - rare
whole eggs, liver, beef steak, and soy (lecithin)
Carnitine - unlikely
meat, dairy products, asparagus,
wheat grem
Bioflavonoids - none known
Lipoic acid - none known
Coenzyme Q - rare
Inositol - none known
p-Aminobenzoic acid - see B9
fruits, vegetables, tea, coffee,
cocoa, wine, beer
liver
fruits, vegetables, meats
cereal grains
liver, rice bran, whole wheat
Role in Pathways
Glycogenolysis
Glycogen
Glc
PP a
vit B6
G1P
Glycolysis
G6P
PPP
R5P
TK
vit B1
G3P
Ala
ALT
vit B6
Pyr
PDH
vit B1,B2,B3
Acetyl-CoA
Asp
AST
vit B6
OA
TCA
cycle
SCoA
vit B6
aKG
aKGDH
vit B1,B2,B3
Glu
Neurotransmitter Overview
PLP (vit B6)
g-Aminobutyrate
Glutamate
deCO2ase
PLP (vit B6)
Tyrosine
Dopamine
Norepinephrine
deCO2ase
Epinephrine
PLP (vit B6)
Tryptophan
Serotonin
deCO2ase
Neurotransmitter Pathway
Catecholamines
PLP (vit B6)
THBP, O2
DOPA
Tyrosine
Dopamine
AAA deCO2ase
Tyr OHase
DbOHase
Vit C, O2
PNMT
Epinephrine
Norepinephrine
SAHC SAM
THBP, O2
PLP (vit B6)
5HTP
Tryptophan
Trp OHase
Serotonin
AAA deCO2ase (5-HT)
Tetrahydrofolate Conversions
Folate
DHF
reductase
(dUMP to dTMP
to DNA)
DHF
DHF
reductase
THF
Most
oxidized
(Ser to
Gly)
(HC to Met)
(His to
Glu)
N10-formyl-THF
N5-formimino-THF
N5,N10-methenyl-THF
N5,N10-methylene-THF
N5-methyl-THF
Most
reduced
Tetrahydrofolate examples
NAD+
THF
PLP
N5,N10MLTHF THF
Ser
NADH + H+
N5,N10MLTHF
CO2 + NH4+
Gly
serine hydroxymethyl
transferase
glycine synthase
N5-FTHF
THF
His
Glu
glutamate formimino transferase
dUMP
dTMP
thymidylate synthase
N5,N10MLTHF
A series of reductases
7,8-DHF
THF
DHF reductase
B12 Pathways
Odd-chain
FA oxidation/
AA metabolism
MMCoA mutase
L-MMCoA
SCoA
Vit B12
(H exchange)
TCA
cycle
Methyl transfers
(1C metabolism)
Met Ad transferase
ATP + Met
S-AdMet
THF
R
Met synthase
Vit B12
N5MTHF
A variety
of MTs
R-CH3
hydrolase
HC
Purines, dTMP
S-AdHC
Review Questions
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What are the different names
for vitamins A, B1, B2, B3, B5, B6,
C, and B12?
Which pathway depends on
vitamin A?
Which pathways and enzymes
depend on vitamin B1, B2, B3, B6
and B12?
Which pathway and enzyme
depends on choline?
Which pathways and enzymes
depend on folic acid?