[Proteinase participation in chromosome radiation damage. Research on the action of phenylmethylsulfonyl fluoride].

Phenylmethylsulfonyl fluoride, a chromatin proteinase inhibitor, caused a nearly twofold diminution of the cytogenetic injury and a twofold increase in the rate of DNA repair in gamma-irradiated (3-15 Gy) Chinese hamster fibroblasts. The effect of the inhibitor was mainly exhibited by a rapidly repaired (for 15-20 min) component of the cytogenetic damage. A simultaneous treatment with phenylmethylsulfonyl fluoride and nicotinamide did not influence the effect of the proteinase inhibitor under study. The results obtained are indicative of poly (ADP-ribosylation)-independent contribution of chromatin proteinases to radiation-induced chromosome mutagenesis.