Cells of the oxygen-evolving halotolerant cyanobacterium Aphanocthece halophytica synthesize betaine from glycine by a three-step methylation process. This is the first enzyme and it leads to the formation of either sarcosine or N,N-dimethylglycine, which is further methylated to yield betaine (N,N,N-trimethylglycine) by the action of EC 2.1.1.157, sarcosine/dimethylglycine N-methyltransferase. Differs from EC 2.1.1.20, glycine N-methyltransferase, as it can further methylate the product of the first reaction. Acetate, dimethylglycine and S-adenosyl-L-homocysteine can inhibit the reaction [3].
Waditee R, Tanaka Y, Aoki K, Hibino T, Jikuya H, Takano J, Takabe T, Takabe T
Title
Isolation and functional characterization of N-methyltransferases that catalyze betaine synthesis from glycine in a halotolerant photosynthetic organism Aphanothece halophytica.