Relationship between inhibition of protein methylase I and inhibition of Rous sarcoma virus-induced cell transformation.

A correlation was found between inhibition of protein methylase I and inhibition of virus-induced cell transformation by structural analogs of S-adenosylhomocysteine; all good inhibitors of this enzyme are also good inhibitors of Rous sarcoma virus-induced chicke embryo fibroblast transformation. The inhibitory effect of these analogs was similar on enzymes from normal and transformed cells; no significant variation of the inhibition constants was observed after purification of protein methylase I. From the kinetic constants obtained, a structure-activity relationship can be established for protein methylase I.