title: Regulation of the methionine feedback-sensitive enzyme in mutants of Salmonella typhimurium.
abstract: Assay of the first enzyme unique to methionine biosynthesis, homoserine-O-transsuccinylase, in metJ and metK regulatory mutants of Salmonella typhimurium showed that synthesis of the enzyme was derepressed seven- and fourfold, respectively. The possibility of noncoordinate regulation of the methionine enzymes is discussed. In metA feedback-resistant mutants, the enzyme activity can be inhibited in vitro by 10 mmS-adenosylmethionine but not by 10 mm l-methionine; hence, the synergistic inhibition found for the wild-type enzyme is not effective in these latter mutants.
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002474:Cell-Free System; D003470:Culture Media; D004357:Drug Synergism; D004794:Enzyme Repression; D005001:Ethionine / Q000494:pharmacology; D005246:Feedback; D005827:Genetics, Microbial; D006714:Homoserine; D007930:Leucine / Q000494:pharmacology; D008715:Methionine / Q000096:biosynthesis / Q000494:pharmacology*; D009154:Mutation; D012436:S-Adenosylmethionine / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D013237:Stereoisomerism; D013386:Succinates
chemical_list: D003470:Culture Media; D013386:Succinates; D006714:Homoserine; D012436:S-Adenosylmethionine; D008715:Methionine; D000217:Acyltransferases; D007930:Leucine; D005001:Ethionine