Direct involvement of nadph oxidase with the stimulated respiratory and hexose monophosphate shunt activities in phagocytizing leukocytes

Abstract

Guinea pig peritoneal exudate polymorphonuclear leukocytes (PMN) have KCN-sensitive and insensitive NADPH oxidation activity. These activities can be localized to different homogenate fractions. NADPH oxidation activity of the 19 000 g pellet is KCN-insensitive. Myeloperoxidase (MPO) activity which is also confined to this fraction is completely inhibited by 1 mM KCN. This observation indicates that KCN-insensitive NADPH oxidation is not due to MPO. KCN-sensitive NADPH oxidation activity is found in the 19 000 g supernatant fraction, as is catalase. Purified beef liver catalase does not oxidize NADPH, thus indicating that the NADPH oxidation by the supernatant is not due to the presence of catalase. NADPH oxidation activity of both the 19 000 g pellet and supernatant fractions collected from phagocytizing cells is significantly greater than that found in the corresponding fractions collected from resting cells. The increased oxidative burst associated with phagocytosis can be accounted for by the stimulated NADPH oxidase activity.