Reaction: S-adenosyl-L-methionine + N,N-dimethylglycine = S-adenosyl-L-homocysteine + betaine
Glossary: betaine = glycine betaine = N,N,N-trimethylglycine
Other name(s): BsmB; DMT
Systematic name: S-adenosyl-L-methionine:N,N-dimethylglycine N-methyltransferase (betaine-forming)
Comments: This enzyme, from the marine cyanobacterium Synechococcus sp. WH8102, differs from 220.127.116.11, sarcosine/dimethylglycine N-methyltransferase in that it cannot use sarcosine as an alternative substrate . Betaine is a 'compatible solute' that enables cyanobacteria to cope with osmotic stress by maintaining a positive cellular turgor.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
1. Lu, W.D., Chi, Z.M. and Su, C.D. Identification of glycine betaine as compatible solute in Synechococcus sp. WH8102 and characterization of its N-methyltransferase genes involved in betaine synthesis. Arch. Microbiol. 186 (2006) 495-506. [PMID: 17019606]