Platelet-collagen interaction : Adhesion of human blood platelets to purified (CB4) peptide from type III collagen

This study was designed to recognize which portion of the type III collagen molecule is involved in platelet adhesion. Calf-skin type III collagen was cleaved with cyanogen bromide and each CNBr peptide was assayed in a quantitative method based upon differential filtration of non adhesive and adhesive ( 14C) serotonin labelled platelets through a Sepharose 2B column. A significant adhesion was induced by the 149 amino acid central CB4 peptide. The other peptides were found to be inactive. Two fragments resulting from the cleavage of CB4 peptide by chymotrypsin and hydroxylamine were tested in our system. The adhesive potency was found to be associated with the 74 amino acid C-terminal fragment of CB4 peptide obtained by hydroxylamine cleavage. These data confirm that elements of the primary structure of collagen are crucial in the adhesion of platelets.