Purine nucleoside phosphorylase from human erythrocytes. 3. Inhibition by the inosine analog formycin B of the isolated enzyme and of nucleoside metabolism in intact erythrocytes and sarcoma 180 cells.

Abstract

Formycin B, an analog of inosine, is a potent competitive inhibitor of purified erythrocytic purine nucleoside phosphorylase. The inhibition constant, Ki (1 x 10-4 M) is of the same order of magnitude as the Km for inosine (5 x 10-5 M). Formycin B also inhibits the degradation of nucleosides by intact and hemolyzed human erythrocytes and by Sarcoma 180 ascites cells.