Biochemische Prozesse bei der Ausl�sung der Blutgerinnung durch Kollagen

Abstract

Biochemical Mechanisms in Inducing o/ Coagulation by Collagen. Summary. Collagen in the wall of blood vessels denuded by lesion of the endothelium activates clotting in two different ways: 1. by reaction with thrombocytes part of which adhere to collagen fibrils and initiate clumping of further platelets, 2. by activation of Hageman-Factor which induces the plasmatic clotting system to form a solid fibrin plug. These activation mechanisms depend on native collagen exhibiting a triple-helicM conformation of peptide chains. Adhesion of thrombocytes may be mediated by s-amino-groups of collagen as well as by incomplete carbohydrate groups attached to the side chains of certain hydroxylysine residues. Activation of Factor XII is promoted by free carboxylic groups of collagen and by the telopeptides. In this way different sites of the same molecule are responsible for the initiation of blood clotting by the two mechanisms. A synergism exists between them.