Inhibition of initiation of protein synthesis by tosyl-L-lysyl chloromethyl ketone.

Tosyl-L-lysyl chloromethyl ketone (TLCK) inhibits protein synthesis in intact cells and lysates. Its presence leads to polyribosome disaggregation. This inhibition is probably at the level of chain initiation because it does not slow poly(U)-dependent elongation of poly(F). This drug activates an inhibitor similar to the heme-controlled repressor in the postribosomal supernatant. High concentrations of ATP and GTP affect inhibitions of translation by the heme-controlled repressor and TLCK in a similar fashion. The latter also interferes with formation of the 40S initiation complex. Its action on translation can be prevented by preliminary incubation with thiols.