[Peptidyltransferase center of ribosomes. II. Effect of temperature on the activity of model peptide donors and a study of oligopeptide formation in a matrix-free system with ribosomes].

The reaction of 3'(2')-O-(N-formylmethionyl)-adenosine 5'-phosphate with Phe-tRNA or CACCA-Phe catalysed with E. coli MRE-600 ribosomes and stimulated with cytidine 5'-phosphate was investigated. It was shown that the reaction with Phe-tRNA was stimulated within 2--3 times when the temperature has been raised from 0 to 40 degrees. On the contrary when the peptide acceptor was CACCA-Phe the yield of peptides synthesis dropped 5 times and more under the same conditions. Similar temperature influence was observed in the reaction with 50S subunits. The inhibition of peptide bond formation with pA and CpA at 0 degrees was achieved up to 80--90% but it was very low at 40 degrees. The synthesis of tri- and tetrapeptides was observed when the reaction of 3'(2')-O-(N-formylmethionyl)-adenosine 5'-phosphate was carried out either with Phe-tRNA or with CACCA-Phe.