The action of phospholipase A on purified phospholipids, plasma and tissue preparations

Publisher Website
Google Scholar
Abstract
The actions of phospholip-ase A on purified lecithin, phosphatidylethanolamine and phosphat-idylserine on the phospholipids in plasma lipoproteins and on the phospholipids present in brain and muscle have been studied in an aqueous reaction system. A partially purified heat-treated human pancreatic phospholipase A and the phospholipase A present in heated freeze-dried cobra venom have been used. The need for activation by deoxycholate, when isolated phospholipids were used as substrates, depended on the type of phospholipid chosen. Phospholipids in plasma were rapidly attacked by the cobra-venom enzyme without activation. The pancreatic enzymed showed only slight activity against plasma unless deoxycholate was added. Both enzymes rapidly hydrolysed the diacyl-phospholipids present in brain and muscle homogenates without the need for activation. They also both attacked the phospholipids in intact brain cells. Cobra-venom enzyme split phospholipids in intact muscle cells but the pancreatic enzyme attacked these only slowly, if at all.