title: Factor VIII/von Willebrand factor protein. Galactose a cryptic determinant of von Willebrand factor activity.
abstract: The normal Factor VIII/von Willebrand factor protein has the ability to agglutinate or aggregate normal platelets in the presence of ristocetin (von Willebrand factor activity). Removal of greater than 95% of the sialic acid from this protein by neuraminidase did not affect the von Willebrand factor or procoagulant activity. However, oxidation of the penultimate galactose of the asialo Factor VIII/von Willebrand factor protein with galactose oxidase resulted in a progressive loss of von Willebrand factor activity with no effect on procoagulant activity. Reduction of the 6-aldehydo intermediate by potassium borohydride caused full regeneration of von Willebrand factor activity. These studies confirm the identification of the intact penultimate galactose moiety as a critical determinant of von Willebrand factor activity.
mesh_terms: D001779:Blood Coagulation Factors / Q000502:physiology*; D055598:Chemical Phenomena; D002621:Chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D005169:Factor VIII / Q000502:physiology*; D005690:Galactose / Q000032:analysis / Q000502:physiology*; D005692:Galactose Oxidase; D009439:Neuraminidase; D014841:von Willebrand Factor / Q000502:physiology*
chemical_list: D001779:Blood Coagulation Factors; D014841:von Willebrand Factor; D005169:Factor VIII; D005692:Galactose Oxidase; D009439:Neuraminidase; D005690:Galactose