title: Hydrolysis of mixed monomolecular films of phosphatidylcholine/triacylglycerol by pancreatic phospholipase A2.
abstract: We studied the effect of glycerides on pancreatic phospholipase A2 hydrolysis of mixed monomolecular films of trioctanoylglycerol/1,2-didodecanoyl-sn-glycero-3-phosphocholine with the technique of Piéroni and Verger [(1979) J. Biol. Chem. 254, 10090-10094]. The quantity of enzyme adsorbed to the interface was concomitantly determined with [3H]amidinated phospholipase. At phospholipid packing above the critical penetration pressure, triacylglycerol stimulates phosphatidylcholine hydrolysis to a great extent. On the other hand, the activity of pancreatic phospholipase A2 on a mixed film is inhibited by the action of pancreatic lipase. Interface binding of phospholipase A2 to the lipid substrate does not imply activity.
mesh_terms: D000818:Animals; D001665:Binding Sites; D004789:Enzyme Activation; D006868:Hydrolysis; D008066:Lipolysis; D010179:Pancreas / Q000201:enzymology; D010713:Phosphatidylcholines / Q000378:metabolism*; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D013329:Structure-Activity Relationship; D013552:Swine; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D010713:Phosphatidylcholines; D014280:Triglycerides; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2