We plan to describe and characterize the O2 and H2O2 producing enzyme(s) of human granulocytes. The individual components of the system (soluble protein, intermediate electron acceptor, final link to O2) will be examined, and the mode of control will be elucidated. Enzymes other than reduced pyridine nucleotide oxidases that produce O2 and H2O2 will also be sought, paricularly amine-oxidases of various kinds. We shall obtain further comparative data (interspecies) on various phagocytid leukocytes, for the sake of clarification of several situations in the literature. In particular, we shall determine in which species the MPO-protein degradation pathway localized in the phagosome, is applicable. We shall complete our exploration of the effects of activation of macrophages (in vivo and in vitro) on enzmes of purine nucleoside metabolism in relation to the diminution of ecto-5'-nucleotidase that is characteristic of activation. We aim to characterize and localize the O2-H2O2 producing enzymes of macrophages (control and activated), and thus to define more closely their role in tumoricidal action. We shall continue our efforts to define the biochemical profile of activated macrophages, with the hope that a definitive biochemical marker for "activation" will emerge.