Water soluble vitamins

Question 1

B1

Answer 1

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

Def = Wernicke-Korsakoff Syndrome

Question 2

B2

Answer 2

Riboflavin

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

Question 3

B3

Answer 3

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

Question 4

B5

Answer 4

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.

Question 5

B6

Answer 5

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)

Question 6

B7

Answer 6

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.

Question 7

B9

Answer 7

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

Question 8

B12

Answer 8

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

Question 9

Integration btwn B9 and B12

Answer 9

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

Question 10

Integration btwn B7 and B12

Answer 10

Works together to turn propionyl CoA to Succinyl CoA

Question 11

Vit C

Answer 11

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