title: Role of phospholipids in the activation of the Ca2+-dependent neutral proteinase of human erythrocytes.
abstract: Activation of the Ca2+-dependent neutral proteinase of human erythrocytes in the presence of Ca2+ and a digestible substrate (Pontremoli, S., Sparatore, B., Melloni, E., Michetti, M. and Horecker, B.L. 1984, Biochem. Biophys. Res. Communs. 123, 331-337) is promoted by phospholipids such as phosphatidylcholine, phosphatidylinositol and phosphatidylserine. The presence of at least one unsaturated fatty acid chain is essential and metabolic derivatives such as dioleylglycerol, phosphorylserine and free fatty acids are ineffective. The most effective promoter was a freshly prepared mixture of phospholipids from human erythrocyte membranes. Activation involves conversion of the 80 kDa proenzyme (procalpain) subunit to the 75 kDa active proteinase and is irreversible. Phospholipids act by producing a large decrease in the concentration of Ca2+ required for the conversion of procalpain to active calpain.
authors.forename: S
authors.initials: S
authors.lastname: Pontremoli
authors.forename: E
authors.initials: E
authors.lastname: Melloni
authors.forename: B
authors.initials: B
authors.lastname: Sparatore
authors.forename: F
authors.initials: F
authors.lastname: Salamino
authors.forename: M
authors.initials: M
authors.lastname: Michetti
authors.forename: O
authors.initials: O
authors.lastname: Sacco
authors.forename: B L
authors.initials: BL
authors.lastname: Horecker
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002154:Calpain; D010450:Endopeptidases / Q000097:blood*; D004789:Enzyme Activation / Q000187:drug effects; D004792:Enzyme Precursors / Q000378:metabolism; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D066298:In Vitro Techniques; D008970:Molecular Weight; D010713:Phosphatidylcholines / Q000494:pharmacology; D010714:Phosphatidylethanolamines / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology*
chemical_list: D004792:Enzyme Precursors; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010716:Phosphatidylinositols; D010743:Phospholipids; D010450:Endopeptidases; D002154:Calpain; D002118:Calcium