Lipocortin inhibition of extracellular and intracellular phospholipases A2 is substrate concentration dependent

• Published in: FEBS letters 1987-07, Vol.219 (1), p.176-180
• Main Authors: Aarsman, A.J., Mynbeek, G., van den Bosch, H., Rothhut, B., Prieur, B., Comera, C., Jordan, L., Russo-Marie, F.
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Annexins; Biological and medical sciences; Blood Platelets - enzymology; Enzymes and enzyme inhibitors; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; Glycoproteins - pharmacology; Humans; Hydrolases; Hydrolysis; Lipocortin; Membrane Lipids - metabolism; Pancreas - enzymology; Phosphatidylethanolamine; Phosphatidylethanolamines - metabolism; Phospholipase A2; Phospholipases - antagonists & inhibitors; Phospholipases A - antagonists & inhibitors; Phospholipases A - metabolism; Phospholipases A2; Phospholipids - metabolism; Rats; Swine
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(87)81212-7

Hydrolysis of Escherichia coli membrane phospholipids by pancreatic phospholipase A2 was inhibited by lipocortin from human monocytes in a substrate dependent manner. Inhibition was completely overcome at substrate concentrations above 250 μM. Lipocortin also inhibited partially purified preparations of two intracellular phospholipases A2, isolated from rat liver mitochondria and rat platelets when these enzymes were assayed at low micromolar concentrations of phosphatidylethanolamine. Inhibition gradually decreased with increasing substrate concentrations both for pancreatic and platelet phospholipase A2 and became completely abolished above 15 and 50 μM phosphatidylethanolamine, respectively.