Solubilization of the O₂^--forming activity responsible for the respiratory burst in human neutrophils

On exposure to suitable activating agents, neutrophils sharply alter their oxygen metabolism, showing large increases in oxygen uptake, O₂ and H₂O₂ production, and glucose consumption via the hexose monophosphate shunt. These metabolic alterations, which together are designated the 'respiratory burst', are due to the activation of a system which catalyzes the reaction: 2O₂ + NADPH → 2O₂^- + NADP. This O₂^--forming system is found in a particulate fraction isolated from neutrophils which had been activated with opsonized zymosan. When these particles were treated with detergent under suitable conditions, the O₂^--forming activity was released in a form which passed through a membrane filter capable of retaining species of Mr >300,000. Soluble O₂^--forming activity was obtained from normal activated neutrophils, but not from normal resting neutrophils or from activated neutrophils obtained from patients with chronic granulomatous disease, an inherited condition in which the respiratory burst is defective. O₂^- production by the soluble system required a reduced pyridine nucleotide as electron donor, and showed a quadratic dependence on the concentration of the solubilized preparation.