Utilization of S-adenosylmethionine by micro-organisms.

Shapiro, Stanley K. (Argonne National Laboratory, Argonne, Ill.). Utilization of S-adenosylmethionine by microorganisms. J. Bacteriol. 83:169-174. 1962.-Two types of mutants of Aerobacter aerogenes that utilize S-adenosylmethionine for growth are described. One type also responds to methionine, 5'methylthioadenosine, or a combination of homocysteine and S-methylmethionine. The second type of mutant responds only to S-adenosylmethionine or a combination of adenine and S-ribosylmethionine. The most common type of methionine mutant is unable to utilize S-adenosylmethionine for growth. The mutants are able to utilize the compounds that support growth as the sole source of sulfur. S-Adenosylhomocysteine is not utilized for growth by any of the mutants of A. aerogenes described here. There are no significant differences between the mutants and the wild type in the enzymatic decomposition of S-adenosylmethionine or in the activity of the homocysteine transmethylases. S-Adenosylmethionine does not replace the methionine requirement of the lactic acid bacteria, although Lactobacillus arabinosus shows half-maximal growth with the sulfonium compound and homocysteine. S-Adenosylhomocysteine is not utilized for growth by these organisms.