Purification and characterization of human platelet phospholipase A2 which preferentially hydrolyzes an arachidonoyl residue.
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.
Takayama
K
K
Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Kudo
I
I
Kim
D K
DK
Nagata
K
K
Nozawa
Y
Y
Inoue
K
K
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
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium