Phagocytosis-induced formate and glucose C-1 oxidation by the polymorphonuclear leukocytes of a patient with hereditary myeloperoxidase deficiency was considerably greater than normal. The addition of catalase to the leukocyte suspension was required for optimum formate oxidation. Azide and cyanide increased glucose C-1 oxidation by normal leukocytes but had little or no effect on myeloperoxidase-deficient leukocytes suggesting that these agents normally stimulate glucose C-1 oxidation, in part, by inhibition of myeloperoxidase. It is suggested that the inhibition or absence of myeloperoxidase results in an increased utilization of H2O2 in nonmyeloperoxidase-mediated H2O2-dependent reactions such as formate oxidation and hexose monophosphate pathway activation. The possibility of a microbicidal control mechanism in which a decrease in the microbicidal activity of myeloperoxidase is offset, in part, by an increase in the nonenzymatic microbicidal activity of H2O2 is considered.
Seymour J. Klebanoff, Stephanie H. Pincus