Effect of 2',3'-dialdehyde NADPH on activation of superoxide-producing NADPH oxidase in a cell-free system of pig neutrophils

We studied the effect of the 2',3'-dialdehyde derivative of NADPH on the activation of superoxide-producing oxidase in a cell-free system of pig neutrophils. The system consisted of a membrane fraction, two cytosolic fractions prepared by gel filtration, and arachidonic acid. Preincubation of one of the cytosolic fractions with the derivatives of NADPH and NADP+ caused the loss of its ability to activate the enzyme. The inactivation was effectively prevented by the addition of NADPH and NADP+. Neither the membrane fraction nor the other cytosolic fraction was affected by the derivatives. The results indicate that the NADPH binding component of the oxidase is present in the cytosolic fraction and may be translocated to the membrane fraction during the activation process in the cell-free system.