May 13, 1976

A phospholipase A2 with anticoagulant activity. II. Inhibition of the phospholiped activity in coagulation

Biochimica Et Biophysica Acta
M C Boffa, G A Boffa

Abstract

An anticoagulant factor with phospholipase A2 activity has been isolated from Vipera berus venom. Phospholipase activity was studied on platelet phospholipid and on brain cephalin. The venom factor showed a potent anticoagulant activity: 1 mug impaired the clotting of 1 ml of citrated recalcified platelet-poor plasma. The anticoagulant inhibited clotting by antagonism to phospholipid. The antagonism constant (Kan = 6.8-10(-9) M) demonstrated the high affinity of the inhibitor for phospholipid. As with other phospholipases A2, the venom factor was thermoresistant but very sensitive to photo-oxidation. Both activities (anticoagulant activity and phospholipase activity) were not markedly dissociated by either denaturation or neutralization processes. Slightly different curves of photo-oxidative inactivation of both activities suggested the presence, on the molecule, of two very close sites responsible for phospholipase and anticoagulant activities. The inhibitor effect on coagulation was independent of the hydrolysis process. In fact, lysoderivatives and fatty acids, resulting from complete hydrolysis with the venom factor, were as active as the native phospholipids. Moreover phospholipase A2 from other viperidae venom, which did ...Continue Reading

Mentioned in this Paper

Snake Venoms
Calcium
Plasma Protein Binding Capacity
SEC23IP
Phospholipids
Indirect Thrombin Inhibitors
Enzyme Inhibitors
Blood Coagulation
Photochemistry
Phospholipase

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