This is a family of related homocysteine S-methyltransferases enzymes: 5-methyltetrahydrofolate--homocysteine S-methyltransferases also known EC:2.1.1.13, [2]; Betaine--homocysteine S-methyltransferase (vitamin B12 dependent), EC:2.1.1.5, [3]; and Homocysteine S-methyltransferase, EC:2.1.1.10, [1].

1: S-methylmethionine metabolism in Escherichia coli. Thanbichler M, Neuhierl B, Bock A; J Bacteriol 1999;181:662-665. PMID:9882684

2: Human methionine synthase. cDNA cloning, gene localization, and expression. Chen LH, Liu ML, Hwang HY, Chen LS, Korenberg J, Shane B; J Biol Chem 1997;272:3628-3634. PMID:9013615

3: Purification, kinetic properties, and cDNA cloning of mammalian betaine-homocysteine methyltransferase. Garrow TA; J Biol Chem 1996;271:22831-22838. PMID:8798461