title: Specific hydrolysis of methionyl-tRNA Met f catalyzed by a purified peptide.
abstract: A peptide initiation factor purified from rat liver and promoting the binding of initiator tRNA and model initiators to 40S and 80S ribosome at an acid pH liberates methionine and N-acetylmethionine from Trna Met f at neutral reaction. Phenylalanyl-tRNA, N-acetylphenylalanyl-tRNA and methionyl-tRNA Met m are not hydrolyzed under the same conditions. Hydrolysis of methionyl-tRNA Met f is stimulated by the presence of the 40S ribosomal subunit and preceeds at 37 degrees C until all the substrate has been split. No hydrolysis of initiator tRNA or N-acetylmethionyl-tRNA Met f occurs at 0 degrees C. Hydrolysis is slightly stimulated by GTP and MG2+ but not by KCl. The binding and hydrolyzing activity associated with a single protein factor may have an important function in regulating the rate of peptide initiation.
mesh_terms: D000107:Acetylation; D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D006868:Hydrolysis; D008099:Liver / Q000378:metabolism*; D008715:Methionine / Q000031:analogs & derivatives; D010448:Peptide Initiation Factors / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D051381:Rats; D012270:Ribosomes / Q000378:metabolism
chemical_list: D010448:Peptide Initiation Factors; D012346:RNA, Transfer, Amino Acyl; D008715:Methionine; D002265:Carboxylic Ester Hydrolases