The effect of pepsin solubilization on platelet aggregation by types I and III collagens.
The effect of pepsin solubilization on the platelet aggregating activity of type I collagen and type III collagen was examined. Pepsin-digested type I collagen was unable to initiate platelet aggregation in either soluble form or as pre-formed fibrils. In contrast, pepsin-digested type III collagen was active in soluble form or as preformed fibrils. Mixtures of type I and type III collagen were assayed for platelet aggregating activity. In soluble form, these mixtures demonstrated elevated activity with increasing type III concentration. When the mixtures were tested as pre-formed fibrils, the rate of aggregation was relatively constant with the combination 75% type III and 25% type I manifesting the highest activity. The lag time for onset of aggregation was also minimized for this same type III/type I ratio. The combinations of the two collagen types formed fibrils which reflected the amounts of types I and III collagens in solution.
D003094:Collagen / Q000145:classification / Q000302:isolation & purification / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D010434:Pepsin A / Q000494:pharmacology*; D010920:Placenta / Q000032:analysis; D010974:Platelet Aggregation / Q000187:drug effects*; D011247:Pregnancy; D012995:Solubility
D003094:Collagen; D010434:Pepsin A