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Lipocortin inhibition of extracellular and intracellular phospholipases A 2 is substrate concentration dependent
Author(s) -
Aarsman A.J.,
Mynbeek G.,
van den Bosch H.,
Rothhut B.,
Prieur B.,
Comera C.,
Jordan L.,
Russo-Marie F.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81212-7
Subject(s) - phosphatidylethanolamine , phospholipase a2 , intracellular , biochemistry , extracellular , phospholipase , annexin , phosphatidylserine , substrate (aquarium) , chemistry , phospholipid , enzyme , phospholipase a1 , egta , biology , phosphatidylcholine , membrane , calcium , cell , ecology , organic chemistry
Hydrolysis of Escherichia coli membrane phospholipids by pancreatic phospholipase A 2 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 A 2 , 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 A 2 and became completely abolished above 15 and 50 μM phosphatidylethanolamine, respectively.