Fig. 1.

Methionine metabolism. AdoMet S-adenosylmethionine, AdoHcy S-adenosylhomocysteine, THF tetrahydrofolate, 5-MTHF 5-methyltetrahydrofolate, AMP adenosine monophosphate. The following enzymes are in circles: MAT methionine adenosyltransferase (E.C.2.5.1.6), GNMT glycine N-methyltransferase (E.C.2.1.1.20), MTs a variety of AdoMet-dependent methyltransferases, SAHH AdoHcy hydrolase (E.C.3.3.1.1), CBS cystathionine β-synthase (E.C.4.2.1.22), MS methionine synthase (5-MTHF-homocysteine methyltransferase) (E.C.2.1.1.13), BHMT betaine-homocysteine methyltransferase (E.C.2.1.1.5), MTHFR methylenetetrahydrofolate reductase (E.C.1.5.1.20), ADK adenosine kinase (E.C.2.7.1.20)