NADPH-oxidation activities in subcellular fractions isolated from resting or phagocytozing human polymorphonuclears

Using a fluorometric assay for the determination of oxidized pyridine nucleotides (NAD[P]+), total and cyanide-resistant NADPH-oxidative activities have been measured in subcellular fractions isolated from resting and phagocytosing human polymorphonuclears. Enzymatic activies responsible for the oxidation of the NADPH have been recovered in the heavy particles (15,000g/15 min), the low-density particles (100,000g/30 min), and the cytosolic fraction. Stimulation of the cells with opsonized zymosan had a different effect on the NADPH-oxidative activities of these subcellular fractions, which suggests the involvement of various types of enzymatic systems in the oxidation of NADPH. The cytosolic fraction interacted strongly with the enzymatic activities occurring in the sedimentable fractions and is therefore thought to play a central role in the regulation of the activation of the oxidative metabolism associated with phagocytosis.