W3-1: Folate/B12 Flashcards Preview

Foundations > W3-1: Folate/B12 > Flashcards

Flashcards in W3-1: Folate/B12 Deck (15)
Loading flashcards...
1
Q

THF vitamin precursor

A

Folate (B9)

2
Q

Functional and storage forms of THF

A

Functional: monoglutamate

3
Q

Congenital defect caused by failure of the neural tube to close prenatally

A

Spina bifida

4
Q

Hereditary folate malabsorption

A

Defective intestinal (absorption) and liver (storage) proton-coupled folate transporters

–>megaloblastic anemia-dTMP cannot be synthsized from dUMP, RBCs grow but do not divide, WBCs also affected

5
Q

Reduction state-changing folate rxns

A
6
Q

DHF reductase inhibitors

A

methotrexate- cancer or RA

trimethoprim-antibacterial

pyrimethamine-antimalarial

7
Q

Action of 5-fluorouracil

A

inhibit thimidylate synthase

8
Q

THF-methyl group combinations

A
9
Q

dTMP synthesis

A
10
Q

Fate of 5-methyl THF

A

donates methyl to cobalamin

11
Q

2 amino acids that add methyls to THF

A
  • Tryptophan (fumate)
  • Serine (for methylene)
12
Q

2 useful forms of cobalamin

A
  • methyl cobalamin
  • adenosyl cobalamin
13
Q

methyl cobalamin rxn

A

homocysteine–>methionine

(to make cysteine)

14
Q

adenosyl cobalamin rxn

A

methylmalonyl-CoA —> succinyl-CoA (to TCA)

**from branched and odd chain fatty and amino acids

15
Q

What is the methyl trap?

A

when a lack of cobalamin traps all the THF as methyl-THF, unable to particiapte in other one-carbon transfers

(methylene form used to make thiamine)