title: Characteristics of a leucine aminoacyl transfer RNA synthetase from Tritrichomonas augusta.
abstract: This study has investigated the characteristics of a leucine aminoacyl transfer RNA synthetase enzyme from Tritrichomonas augusta. Differential centrifugation and DEAE-cellulose column chromatography were used for partial enzyme purification. The column purification increased the synthetase activity 125-fold over the unfractionated cell extract. The conditions for maximum [3H] leucine charging were 37 degrees C for 20 min, with protein at 180 micrograms ml-1 using yeast leucine tRNA as an acceptor. The optimal reaction conditions were 14 mM-Mg acetate, 3 mM-ATP, 3 mM-spermidine and 5.5 mM-putrescine. Acceptor activity with T. augusta transfer RNA was 8-fold higher than with yeast transfer RNA and 25-fold higher than with Escherichia coli transfer RNA. The partially purified enzyme fraction had comparable changing activities for both leucine and valine.
authors.affiliation: Department of Biochemistry, University of Illinois, Urbana 61801.
authors.forename: J
authors.initials: J
authors.lastname: Horner
authors.forename: W S
authors.initials: WS
authors.lastname: Champney
authors.forename: R
authors.initials: R
authors.lastname: Samuels
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002499:Centrifugation, Density Gradient; D002848:Chromatography, DEAE-Cellulose; D007930:Leucine / Q000378:metabolism*; D014318:Tritrichomonas / Q000201:enzymology*
chemical_list: D000604:Amino Acyl-tRNA Synthetases; D007930:Leucine