Phospholipase A activity associated with membranes of human polymorphonuclear leucocytes.
Homogenates of human polymorphonuclear leucocytes (granulocytes) contain a Ca2+-dependent phospholipase A with optimal activity pH7.0. This enzyme is membrane-bound and is enriched in crude cytoplasmic-granule fraction. Ratezonal centrifugation of the cytoplasmic-granule fraction demonstrates that the phospholipase A is associated not only with specific- and azurophilic-granule populations but also with an 'empty' vesicular fraction containing 85% of the total alkaline phosphatase activity of whole homogenate. Thus this phospholipase is associated with granule as well as with other cellular membranes of human granulocytes.
D000328:Adult; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D002499:Centrifugation, Density Gradient; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009504:Neutrophils / Q000201:enzymology*; D010740:Phospholipases / Q000378:metabolism*
D010740:Phospholipases; D002118:Calcium