Identification of a surface protein of the XXXX blood platelet with high affinity for collagen.

@entity1133 @entity1219 @entity4527 @entity95 @entity2975 @entity214
Platelet membrane components adhering with high affinity to collagen fibers were studied by means of an affinity column in which fibrillar type I collagen was physically immobilized. Intact @entity95 platelets in 1 mM @entity4527 adhered to the column but did not aggregate. Adhesion was dependent on the collagen concentration and on the number of platelets applied. Passage through the column without adhesion did not affect the potential for subsequent platelet binding. Surface-labelled whole platelets were passaged through this column, lysed in Triton and in @entity214 and labelled components adhering to the collagen were analysed on @entity214 - @entity2975 gels. It was found that Triton lysis removed most of the major surface glycoproteins but left the cytoskeleton on the column. Subsequent @entity214 elution removed the cytoskeletal proteins along with the remaining major surface glycoproteins. The label left on the column could not be eluted with 8 M @entity1133 or up to 4 M @entity1219 . Collagenase digestion of the column collagen released a single surface glycoprotein of Mr 80,000. Limited chymotryptic digestion of the labelled platelets prior to their application to the column did not affect their binding. A radiolabelled band of the same molecular weight (MW) became bound to the collagen following passage of the chymotrypsin-treated platelets. This band was trypsin-sensitive following @entity214 - @entity2975 gel electrophoresis ( @entity214 -PAGE). These results, along with other published evidence, suggest that at least one platelet membrane component, expressed on the surface of the unstimulated platelet, binds with high affinity to fibrillar type I collagen and is probably involved in platelet collagen recognition.
