title: Purification and characterization of a tRNA methylase from Salmonella typhimurium.
abstract: A tRNA methylase, in which supK strains of Salmonella typhimurium are deficient, was purified from strain LT2 and characterized. Column chromatography of protein extracts from wild-type cells on phosphocellulose, diethylaminoethyl-Sephadex A-50, and hydroxlapatite resulted in an enzyme that was estimated to be about 50% pure. tRNA from S. typhimurium which had been incubated at pH 9.0 served as a substrate for this methylase. The enzyme has a molecular weight of about 50,000 as estimated by gel chromatography and by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. The optimal assay conditions, as well as the kinetics and stability of the enzyme, were studied. As with other tRNA-methylating enzymes, S-adenosylhomocysteine is a potent inhibitor.
mesh_terms: D007700:Kinetics; D008970:Molecular Weight; D012329:RNA, Bacterial / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012435:S-Adenosylhomocysteine / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000201:enzymology*; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013696:Temperature; D012359:tRNA Methyltransferases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D012329:RNA, Bacterial; D013439:Sulfhydryl Reagents; D012343:RNA, Transfer; D012435:S-Adenosylhomocysteine; D012359:tRNA Methyltransferases