Effects of cobalamin and folic acid on DNA synthesis
Effects of cobalamin and folic acid on DNA synthesis
Interdependent cofactor activity of cobalamin and folate in intracellular DNA synthesis and metabolism. The + signs indicate enhancement, and the - signs indicate inhibition. Demethylation of methyl-tetrahydrofolate (CH3-THF) to THF is a critical step in DNA synthesis because THF is the substrate for the enzyme that converts (THF)-1 to the polyglutamated form (THF)n. Only polyglutamated (THF)n participates in purine synthesis.
CH3-THF: methyl-tetrahydrofolate.
Reproduced with permission from Tefferi, A, Pruthi, RK. The Biochemical Basis of Cobalamin Deficiency. Mayo Clin Proc 1994; 69:181