Fig. 1.

Schematic representation of the folate cycles and homocysteine metabolism. AdoHcy S-adenosylhomocysteine, AdoMet S-adenosylmethionine, AICAR 5-aminoimidazole-4-carboxamide ribonucleotode, SAHH S-adenosylhomocysteine hydrolase, ATP adenosine triphosphate, BHMT betaine-homocysteine methyltransferase, CBS cystathionine β-synthase, CTH cystathionine γ-lyase, DHF dihydrofolate, DHFR dihydrofolate reductase, dUMP deoxyuridine monophosphate, dTMP deoxythymidine monophosphate, FAICAR formyl-AICAR, MAT methionine-adenosyltransferase, MTHFD methylenetetrahydrofolate dehydrogenase / methenyltetrahydrofolate cyclohydrolase / formyltetrahydrofolate synthetase, MTHFR methylenetetrahydrofolate reductase, MTR methionine synthase, MTRR methionine synthase reductase, SHMT serine-hydroxymethyltransferase, THF tetrahydrofolate, TYMS thymidylate synthase