Properties of platelet phospholipase A2.
Thrombin, within seconds after its addition, stimulated the release of 1-14C-20:4n-6 from the platelet phospholipids, phosphatidylcholine and phosphatidylinositol. Although inhibitors of prostaglandin cyclooxygenase did not inhibit this PLA2 activity, the anti-malarial drug, quinacrine, did. The location of the PLA2 that furnishes 20:4n-6 for the cyclooxygenase is not clear, but if it were in or near membranes containing the cyclooxygenase, phospholipids in the vicinity might serve as the source of 20:4n-6. How substrate specificity relates to the asymmetric distribution of the various phospholipid classes in membranes is yet to be determined.
D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology*; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D010740:Phospholipases / Q000097:blood*; D010743:Phospholipids / Q000097:blood*; D011796:Quinacrine / Q000494:pharmacology; D013917:Thrombin / Q000378:metabolism
D005230:Fatty Acids, Nonesterified; D010743:Phospholipids; D003094:Collagen; D010740:Phospholipases; D013917:Thrombin; D011796:Quinacrine; D006854:Hydrocortisone; D004837:Epinephrine