Effects of Valine on Protein Synthesis and Turnover in Pseudomonas saccharophilaunder “Nongratuitous” Inducing Conditions

Under “nongratuitous” inducing conditions, in Pseudomonas saccharophila, d-and l-valine and l-isoleucine inhibit net protein synthesis. At a concentration of 0.5 μmole or greater of valine per mg of bacterial protein, net protein synthesis declined approximately 70%. The inhibitory effect of valine is proportional to the exogenous valine concentration. Studies of 14C amino acid incorporation and 14C amino acid release from prelabeled cells indicate that valine stimulates protein turnover.