Phagocytic vesicles from rabbit lung macrophages produced superoxide in the presence of NADH or NADPH. At 37°C, these vesicles generated 51±7.8 nmol O2−/min per mg protein in the presence of 0.5 mM NADPH. The apparent Km for NADPH and NADH (66 and 266 μM, respectively), the pH optimum for the reaction (6.9), and the cyanide insensitivity were similar to properties of plasma membrane-rich fractions of stimulated polymorphonuclear leukocytes studied by others. The activity of the phagocytic vesicles was trypsin sensitive. The specific superoxide-generating activity of macrophage phagocytic vesicles isolated from cells incubated up to 90 min with phagocytic particles remained constant.
P. Daniel Lew, Thomas P. Stossel