title: Purification and characterization of human platelet phospholipase A2 which preferentially hydrolyzes an arachidonoyl residue.
abstract: A phospholipase A2 with an arachidonoyl residue preference was purified about 11,700-fold from human platelet soluble fraction to near homogeneity. The purified phospholipase A2 exhibited a molecular mass of about 90 kDa on SDS polyacrylamide gel electrophoresis and hydrolyzed phospholipids with an arachidonoyl residue more effectively than those with a linoleoyl residue. The catalytic activity of the purified enzyme detected with phosphatidylcholine as a substrate increased sharply between 3 x 10(-7) and 10(-6) M free calcium ion. Thus, the 90-kDa phospholipase A2 is considered to be a novel enzyme, distinct from the 14-kDa one previously purified from human platelets. The 90-kDa phospholipase A2 may participate mainly in arachidonate metabolism of platelets.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takayama
authors.forename: I
authors.initials: I
authors.lastname: Kudo
authors.forename: D K
authors.initials: DK
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Nagata
authors.forename: Y
authors.initials: Y
authors.lastname: Nozawa
authors.forename: K
authors.initials: K
authors.lastname: Inoue
mesh_terms: D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D001792:Blood Platelets / Q000201:enzymology*; D002118:Calcium / Q000494:pharmacology; D002845:Chromatography; D006801:Humans; D008970:Molecular Weight; D010741:Phospholipases A / Q000097:blood* / Q000378:metabolism; D054467:Phospholipases A2; D013379:Substrate Specificity
chemical_list: D001095:Arachidonic Acids; D016718:Arachidonic Acid; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium