What is ristocetin cofactor activity?

By William Aird

  • Functional assay that measures the ability of ristocetin to promote platelet aggregation in the presence of von Willebrand factor (vWF).
  • Ristocetin is an antibiotic found to agglutinate platelets due to binding of vWF and platelet glycoprotein Ib (GPIb).
  • Ristocetin binds to vWF, inducing a conformational change in vWF which increases its binding to platelets.