Influence of cycloheximide on the synthesis and utilization of amino acids in suspension cultures.

Cells from 4-days old suspension cultures of Paul's Scarlet rose were incubated with acetate-U-(14)C for 10 minutes. After washing, cells were incubated for 2 hours in growth medium in the presence and absence of cycloheximide. The (14)C content of individual amino acids in the soluble form and in protein were determined at the end of the 10 minute pulse and at intervals thereafter in control cells and those treated with cycloheximide. During the period following the pulse there was a 3-fold increase in the (14)C content of protein in control cells; no such increase occurred in the presence of cycloheximide.In the control cells there was a net increase in the (14)C content of eight individual amino acids during this period. For six of these, the corresponding increases in the presence of cycloheximide were curtailed by the following amounts: arginine 98%, lysine 94%, isoleucine 93%, threonine 82%, valine 49%, and proline 36%. This is interpreted to mean that the synthesis of each of these amino acids was slowed down when their incorporation into protein was prevented.