Copy of vitamins

8/7/2019 Copy of vitamins

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Vitamin & Koenzyme


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Some enzymes require no chemical groups for activity other than

their amino acid residues.

Others require an additional chemical component called a

cofactoreither one or more inorganic ions, such as Fe2+, Mg2+,

Mn2+, or Zn2+, or a complex organic or metalloorganic molecule

called a coenzyme

Some enzymes require both a coenzyme and one or more metal

ions for activity.

A coenzyme or metal ion that is very tightly or even covalently

bound to the enzyme protein is called a prosthetic group.A complete, catalytically active enzyme together with its bound

coenzyme and/or metal ions is called a holoenzyme. The protein

part of such an enzyme is called the apoenzyme orapoprotein


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Cofactor

coenzyme

prosthetic group

inorganic ions

(activator)

Many are derivatives of vitamins.


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Vitamins

Eric Niederhoffer

SIU-SOM

A retinol phototransduction

D cholecalciferol bone remodeling

E tocopherols antioxidant

K phytylmenaquinone

multiprenylmenaquinonecoagulation

bone remodeling

B1 thiamine carbohydrate metabolismB2 riboflavin redox, respiration

B3 niacin redox

B6 pyridoxinepyridoxamine

pyridoxal

aa metabolismglycogenolysis

B5 Pantothenic acid tca, fa and cholesterol

B7 Biotin gluconeogenesis, tca, fa, aa

B12 cobalamin 1C&H metabolism

B9 Folic acid 1C metabolism

C ascorbic acid hydroxylation

Choline ac, pl


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Glycolysis

TCA

cycle

Glycogenolysis

EKGDH

vit B1,B2,B3

PP a

vit B6

Glc

Glycogen

G1PR5P

TK

vit B1

PDH

vit B1,B2,B3

EKGSCoA

Acetyl-CoA

G6P

Pyr

G3PALT

vit B6Ala

ASTvit B6

OAAsp

vit B6 Glu

PPP

Vitamins in Pathways


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His Gluglutamate formimino transferase

THF N 5-FTHF

Ser Glyserine hydroxymethyl transferase

CO2+ NH4+

glycine synthase

THFN5,N10-MLTHF

PLPTHF

NAD+ NADH + H+

N5,N10-MLTHF

dUMP dTMP thymidylate synthase

N5,N10-MLTHF 7,8-DHF


THF DHF reductase


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THF N 5,N10-methylene-THF

N5,N10-methenyl-THF

N5-formyl-THF

N10-formyl-THF

N5-methyl-THF most reduced

N5-formimino-THFmost oxidized

Tetrahydrofolate Conversions

Folate

DHF

DHF reductase

DHF reductase


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L-MMCoA SCoA

Met S-AdMet

S-AdHCHC

ATP +

Methyl transfers

(1C metabolism)

Met synthase

Vit B12

TCA

cycle

Odd-chainFA oxidation

MMCoA mutase

Vit B12(H exchange)

Met Ad transferase

A variety

of MTs

hydrolase

THF

N5MTHF

R

R-CH3

Purines, dTMP


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Vitamin Deficiencies and Sources

A - night blindnesspreformed: liver, egg yolk, butter, milk

F-carotene: dark green and yellow veggies

D - ricketts, osteomalaciamilk, fortified food, fish oils, egg yolks, liver

E - neurologic?, hemolytic anemia veggie oils, nuts

K - bleeding disorders green leafy veggies, fruits, dairy products, veggie oils, cereals, meats

B1 - beri-beri seeds, nuts, wheatgerms, legumes, lean meat

B2- pellagra meats, nuts, legumes

B3 - pellagra meats, nuts, legumes

B6- neurologic diseaseyeast, liver, wheatgerm, nuts, beans, bananas

B7- widespread injurycorn, soy, egg yolk, liver, kidney, tomatoes

B12- pernicious anemia liver, kidney, egg, cheese

B9 - anemia yeast, liver, leafy veggies

C - scurvy citrus and soft fruits

Choline - rare whole eggs, liver, beef steak, and soy (lecithin)

B5- none known yeast, grains, egg yolk, liver


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Review Questions 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, B6and B12?

Which pathways and enzymes depend on folic acid?

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