Propolypeptide and mature portions of von Willebrand factor of bovine origin recognize different sites on type‐I collagen obtained from bovine tendon

Abstract

We compared the binding of propolypeptide and mature portions of von Willebrand factor of bovine origin to fibrillar type-I collagen obtained from bovine tendon. The propolypeptide (pp-vWF) and the mature portion (m-vWF) of human origin consist of 741 and 2050 amino acids, respectively, and are rather large proteins. The collagen-binding properties of the two proteins of bovine origin were similar in that both bound more avidly to native collagen than to heat-denatured collagen. Bindings was affected similarly by ionic strength but was not modified either by divalent cations or a synthetic peptide containing Arg-Gly-Asp. However, the binding sites in the fibrillar type-I collagen molecule for pp-vWF and m-vWF seem to be different: the two proteins did not effectively compete with each other for binding to collagen. Furthermore, pepsin treatment of fibrillar type-I collagen resulted in a drastic decrease in the binding of pp-vWF, while only a moderate decrease in the binding of m-vWF was observed after the treatment.