Inhibition by suramin of the NADPH oxidase from horse polymorphonuclear leukocytes

Suramin strongly inhibits the NADPH dependent oxidative activity of the plasma membrane fraction from activated horse polymorphonuclear leukocytes. The kinetics of inhibition reveals the existence of one effective binding site located on the inner surface of the plasma membrane with an apparent Ki value for suramin of about 1 mM. Although administration of suramin to intact cells does not affect the immediate respiratory burst, prolonged preincubation in vitro with the drug results in a decrease of H2O2 production without lowering the phagocytic activity of the leukocytes. Possible implications in vivo are briefly discussed.