title: The identification of the tRNA substrates for the supK tRNA methylase.
abstract: Purified preparations of the tRNA methylase deficient in supK strains of Salmonella typhimurium transfer methyl groups from S-adenosylmethionine (SAM) to at least two tRNA species, an alanine tRNA and a serine tRNA. The identity of the tRNA substrates for this enzyme was determined by a change in the elution position of the methyl-labeled tRNA from BND-cellulose columns before and after aminoacylation with a specific amino acid followed by derivatization of the free primary amino group with phenoxy- or naphthoxyacetate. The radioactive methyl group enzymatically added to these tRNAs is both acid and base labile and can be hydrolyzed to a volatile product at pHs above 7.5 and also at pH 1. The methylated 3'-nucleotide isolated from digested tRNA is a pyrimidine derivative and chromatographs like a modified uridylic acid. Its identity has not been established, but it is likely that it corresponds to the methyl ester of V, uridin-5-oxyacetic acid.
mesh_terms: D000409:Alanine / Q000378:metabolism; D000926:Anticodon; D006868:Hydrolysis; D012329:RNA, Bacterial / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000201:enzymology; D012694:Serine / Q000378:metabolism; D014529:Uridine / Q000031:analogs & derivatives* / Q000378:metabolism; D012359:tRNA Methyltransferases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000926:Anticodon; D012329:RNA, Bacterial; D012694:Serine; D012343:RNA, Transfer; D012359:tRNA Methyltransferases; D000409:Alanine; D014529:Uridine