Schematic representation of homocysteine/folate metabolism.

AdoMet indicates S-adenosylmethionine; AdoHcy, S-adenosylhomocysteine; DHF, dihydrofolate; THF, tetrahydrofolate; BHMT, betaine-homocysteine methyltransferase; CBS, cystathionine β-synthase; CH, 5,10-methenylTHF cyclohydrolase; FS, 10-formylTHF synthase; MTHFD, 5,10-methylenetetrahydrofolate dehydrogenase; MTHFR, 5,10-methylenetetrahydrofolate reductase; MTR, methionine synthase; MTRR, methionine synthase reductase; SHMT, serine hydroxymethyltransferase; and TS, thymidylate synthase.