ACTION OF THROMBIN ON SURFACE GLYCOPROTEINS OF HUMAN PLATELETS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 53  (3) , 437-445
Abstract
Surface glycoproteins of human platelets were labeled by the neuraminidase-galactose oxidase/borotritiide and the periodate/borotritiide methods. When labeled platelets were treated with 1-nM thrombin, a minor glycoprotein weighing 68,000-85,000 d [daltons] was lost from the surface, and a soluble glycoprotein weighing 57,000-68,000 d was found in the supernatant. Treatment of platelets with ADP, collagen or the Ca ionophore A23187 [2-3,9,11-trimethyl-8-2 pyrrole carboxymethyl-1,7 dioxaspiro [6.6] undecyl-2 methyl-5 methyl amino benzoxazole-4 carboxylic acid] did not cause loss of the 68,000-85,000 d glycoprotein from platelet surfaces or appearance of the 57,000-68,000 d glycoprotein in the supernatant. Trace amounts of the intact 68,000-85,000 d glycoprotein were found in the supernatants of platelets that were not treated with thrombin. The numerous effects of thrombin on platelets could be initiated by cleavage and release the thrombin-sensitive glycoprotein.