P1 BIOCHEM B12 METABOLISM Flashcards
synthetic form of folate
folic acid
the increase in affinity of folate for folate enzymes is due to
the added glutamic acid residues
reduced & active form of folic acid
tetrahydrofolate TH4 / FH4
enzyme that forms the active form of folic acid
dihydrofolate reductase
enzyme that hydrolyses dietary folates in intestinal lumen
γ-glutamyl hydrolase (folate conjugase)
Transmembrane carries that mediates folate uptake
SLCA19A1 antiporter
SLC46A1 proton coupled
storage site for folate
liver & red cells
form of folate for storage
methyl TNF / polyglutamate
the enzyme dihydrofolate reductase requires how many molecules of NADPH
2
with what drug will folate catabolism be accelerated
methotrexate treatment
Anticonvulsant drugs
mention 3 disorders caused by folate def.
- megaloblastic anemia
- NTD
- MTHFR def.
MOA of methotrexate
- irreversible competitive inhibitor of dihydrofolate reductase - ultimately inhibiting DNA and RNA synthesis.
MOA of Sulfamethoxazole
inhibits the bacterial synthesis of DHF
MOA of Pyrimethamine (anti-malarial drug) & Trimethoprim (anti-bacterial drug)
inhibits DHFR and prevents the synthesis of THF
Transport protein of B12 from diet to ileum
Intrinsic factor
Transport protein of B12 from ileum to tissues
Transcobalamins 1,2,3
B12 is important in converting what coenzyme to succinyl CoA in krebs cycle
Converting methylmalonyl CoA
type of B12 anemia that is due to lack of intrinsic factors
Pernicious anemia
levels of which acid will accumulate incase of V12 Def.
Methylmalonic acid
elevated levels of MMA and what other acid can cause myelin damage
MMA & homocysteine
