Inhibition of Platelet-Collagen Interaction by Propolypeptide of von Willebrand Factor

摘要: Abstract A collagen-binding glycoprotein was isolated from human platelets using affinity chromatography of immobilized collagen. Based upon characterizations this protein we confirmed that it identical to the propolypeptide von Willebrand factor (pp-vWF), which is also called antigen II. The characteristics have investigated are molecular weight, existence carbohydrate chains, and NH2-terminal amino acid sequence. pp-vWF has strong collagen inhibits collagen-induced aggregation at a concentration as low 2 micrograms/ml even in presence plasma. This inhibitory effect specific for since does not inhibit induced by other agonists such ADP, arachidonic acid, platelet-activating factor, ionophore A23187, ristocetin. As quickly released activation various agonists, possible functions repressor excess platelet constitutes negative feed-back mechanism. Considering fact mature vWF supports adhesion subendothelium, present observations suggest propeptide portion could opposing effects on hemostasis.