Differences in mechanisms for cell-free NADPH oxidase activation between arachidonate and sodium dodecyl sulfate.

Abstract

Mechanisms for the cell-free activation of NADPH oxidase by sodium dodecyl sulfate (SDS) and arachidonate were compared in relation to their responsiveness to short chain diacylglycerols. The plasma membrane and cytosol prepared from guinea pig neutrophils were used for the cell-free system. The activation of NADPH oxidase by SDS was enhanced about 5- to 10-fold by 1,2-dioctanoylglycerol (diC8), but not by either 1,2-dihexanoylglycerol (diC6) or 1,2-didecanoylglycerol (diC10). However, none of these diacylglycerols potentiated the NADPH oxidase activation by arachidonate. The maximal extent of activation by the combination of SDS and diC8 was similar to that by arachidonate alone. In the presence of sufficient amounts of diC8 and SDS, GTP gamma S potentiated the activation of NADPH oxidase. The potentiating activity of diC8 was preserved in the membrane fraction, not in the cytosol fraction. These results suggest that arachidonate may possess the functions of both SDS and diC8 in the activation. In addition, diC8 and GTP gamma S seem to independently enhance the NADPH oxidase activation.