Synthetic inhibitors of Escherichia coli, calf thymus, and Ehrlich ascites tumor thymidylate synthetase

Abstract

In a study of active site binding, the inhibition of thymidylate synthetase derived from E. coli, calf thymus and Ehrlich ascites tumor was examined using 8 inhibitors. 5-Substituted 2''-deoxyuridine 5''-phosphate analogues used were the hydroxymethyl, methoxymethyl, benzyloxymethyl, formyl, acetyl, allyl and 2 potential active site alkylating substituents: 2,3-oxypropyl and the azidomethyl analogues. All compounds were competitive with the substrate, 2''-deoxyuridine 5''-phosphate; the most potent inhibitor was 5-formyl-dUMP (Ki [inhibiting constant] = 0.1, 0.09, and 0.08 .mu.M for the respective enzyme). The 5-hydroxymethyl, 5-benzyloxymethyl and 5-azidomethyl derivatives of dUMP showed some differential inhibition; these compounds were 2-3 times more active against the ascites tumor enzyme than against the thymus enzyme.