Reaction: 3 S-adenosyl-L-methionine + glycine = 3 S-adenosyl-L-homocysteine + betaine (overall reaction)
(1a) S-adenosyl-L-methionine + glycine = S-adenosyl-L-homocysteine + sarcosine
(1b) S-adenosyl-L-methionine + sarcosine = S-adenosyl-L-homocysteine + N,N-dimethylglycine
(1c) S-adenosyl-L-methionine + N,N-dimethylglycine = S-adenosyl-L-homocysteine + betaine
Glossary: sarcosine = N-methylglycine
betaine = glycine betaine = N,N,N-trimethylglycine
Other name(s): GSDMT; glycine sarcosine dimethylglycine N-methyltransferase
Systematic name: S-adenosyl-L-methionine:glycine(or sarcosine or N,N-dimethylglycine) N-methyltransferase [sarcosine(or N,N-dimethylglycine or betaine)-forming]
Comments: Unlike EC 2.1.1.156 (glycine/sarcosine N-methyltransferase), EC 2.1.1.157 (sarcosine/dimethylglycine N-methyltransferase) and EC 2.1.1.161 (dimethylglycine N-methyltransferase), this enzyme, from the halophilic methanoarchaeon Methanohalophilus portucalensis, can methylate glycine and all of its intermediates to form the compatible solute betaine [1].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Lai, M.C., Wang, C.C., Chuang, M.J., Wu, Y.C. and Lee, Y.C. Effects of substrate and potassium on the betaine-synthesizing enzyme glycine sarcosine dimethylglycine N-methyltransferase from a halophilic methanoarchaeon Methanohalophilus portucalensis. Res. Microbiol. 157 (2006) 948-955. [PMID: 17098399]