Glycine/sarcosine/dimethylglycine N-methyltransferase

Glycine/sarcosine/dimethylglycine N-methyltransferase (, GSDMT, glycine sarcosine dimethylglycine N-methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:glycine(or sarcosine or N,N-dimethylglycine) N-methyltransferase (sarcosine(or N,N-dimethylglycine or betaine)-forming). This enzyme catalyses the following chemical reaction


 * 3 S-adenosyl-L-methionine + glycine $$\rightleftharpoons$$ 3 S-adenosyl-L-homocysteine + betaine (overall reaction)
 * (1a) S-adenosyl-L-methionine + glycine $$\rightleftharpoons$$ S-adenosyl-L-homocysteine + sarcosine
 * (1b) S-adenosyl-L-methionine + sarcosine $$\rightleftharpoons$$ S-adenosyl-L-homocysteine + N,N-dimethylglycine
 * (1c) S-adenosyl-L-methionine + N,N-dimethylglycine $$\rightleftharpoons$$ S-adenosyl-L-homocysteine + betaine

This enzyme from the halophilic methanoarchaeon Methanohalophilus portucalensis can methylate glycine and all of its intermediates to form the compatible solute trimethylglycine.