Water soluble vitamins Flashcards Preview

MCB 2 Block 3 > Water soluble vitamins > Flashcards

Flashcards in Water soluble vitamins Deck (11):
1

B1

Thiamin
Gets turned into Thiamine Pyrophosphate (TPP). Involved in the transfers f 2 carbon keto groups.

Def = Wernicke-Korsakoff Syndrome

2

B2

Riboflavin
Precursor to FAD and FMN, involved in redox reactions. Destroyed by UV light

3

B3

Nicotinic Acid (niacin)
Precursor for NAD and NADP. In humans, trp degradation yields small amounts of niacin and rqrs b1 and b2

Def = limits in dietary trp limits niacin prod

4

B5

Panthothenic Acid
Bioactive portion of CoASH. Part of Acyl carrier protein (ACP) of fatty acid synthase complex. Functions in acyl group transfer. essential in multienzyme systems. Forms thioester bonds.

5

B6

Pyridoxine
Active form is pyridoxal phosphate (PLP), schiff base. Plays role in aminotransferases, non ox decarb, and ALA synthase. Toxic at high lvls (other water soluble vits excreted in urine)

6

B7

Biotin
Prosthetic group of ATP-dependent carboxylases (pyruvate, acetyl CoA, and propionyl CoA). Also a schiff base
Def is uncommon, Avidin in raw egg whites disables therefore preventing b7 uptake

Breakup of enzymes containing biotin releases biocytin which is broken by biotinidase (def = biotin def) releasing it for reuse.

7

B9

Folate/ Folic Acid
Supplied solely from fiet (plants and bact). used to make THF and BH4 (THF=methylation, BH4=hyrdoxylation)

Def = impaired DNA synth leading to spina bifida and anencephaly

Methotrexated (humans and microbes) and Sulfanamides (microbes) inhibit THF formation

8

B12

Cobalamin
Comes from animal products and has cobalt in it. Enzymes = adenosylcobalamin (methylmalonyl CoA mutase) and methylcobalamin (methionie synthase with THF-Me). Requires intrinsic factor from parietal cells

Defect due to pernicious anemia

9

Integration btwn B9 and B12

Folate trap = TH4 synth stops prior to last step at methyltetrahydrofolate due to B12 def

10

Integration btwn B7 and B12

Works together to turn propionyl CoA to Succinyl CoA

11

Vit C

Ascorbic Acid
Most comes from diet, reducing agent and scavenger of free radicals. Dound mostly in metabolic tissue. Uptake requires Na-dependent transporters. Continuous recycle with GSH and NADPH.

Hydroxylation function

Def=scurvy