| Abstract: | The O2(-)-forming respiratory burst oxidase is present in a dormant state in a fully soluble system containing both cytosol and a deoxycholate extract of membranes from resting human neutrophils. Sodium dodecyl sulfate at low concentrations converts this soluble dormant oxidase into its catalytically active form. The Vmax for the activated oxidase was 2.1 mumol of O2-/min/mg of membrane protein. Michaelis constants for NADPH and NADH (38 microM and 1.7 mM, respectively) were similar to those measured previously in other systems. Oxidase activity was not detected after sodium dodecyl sulfate treatment of systems containing solubilized neutrophil membranes obtained from patients with X-linked chronic granulomatous disease. These results suggest that the deoxycholate extract contains both the resting oxidase and those membrane-associated components needed for its activation, all in functioning states. |
