Detection of arachidonoyl-selective phospholipase A2 in human neutrophil cytosol.

The present report describes the presence of an arachidonic-acid-selective, dithiothreitol-insensitive phospholipase A2 enzyme activity in human neutrophil cytosol. The enzyme activity is eluted from Mono Q FPLC column between 350 to 450 mM salt and translocates from cytosol to membrane in a calcium dependent fashion. Furthermore, the PLA2 activity in the cytosol is quantitatively precipitated by the antibodies against U937 cPLA2. The neutrophil enzyme also migrates as approximately 110 kDa protein on SDS polyacrylamide gels. These studies indicate that the PLA2 enzyme present in human neutrophil cytosol is identical to the previously reported U937 cPLA2 (Clark et al. (1990) Proc. Natl. Acad. Sci. USA 87, 7708 and Clark et al. (1991) Cell 65, 1043).