A Thrombin-Sensitive Protein of Human Platelet Membranes

TLDR

The action of thrombin on intact human platelets was examined by polyacrylamide gel electrophoresis in sodium dodecylsulfate. Thrombin treatment of intact platelets rapidly (within 2 min) hydrolyzes a 190 kDa membrane protein to produce a 107 kDa fragment, an effect that is absent when platelets are disrupted or the protein is solubilized beforehand, suggesting the cleavage triggers thrombin’s platelet actions.

Abstract

The action of thrombin on intact human platelets has been studied with the aid of polyacrylamide gel electrophoresis in sodium dodecylsulfate. A single major membrane protein band with a molecular weight of 190,000 disappears after thrombin treatment, while a new membrane protein with a molecular weight of 107,000 appears. This may represent hydrolysis of the thrombin-sensitive protein. When platelets are disrupted or when the thrombin-sensitive protein is solubilized from membranes prior to thrombin treatment, no hydrolysis occurs. The effect of thrombin on the platelet membrane protein is complete within 2 min which suggests that hydrolysis of this membrane protein may trigger the physiological effects of thrombin on platelets.