Mechanism of calcium-induced reptilase clot retraction.

Calcium ions induce retraction of reptilase clots. This could also be induced by thrombin. Heparin inhibited the reptilase clot retraction induced either by thrombin or calcium, but did not influence the clot retraction induced by ADP. This indicated that the clot retraction induced by Ca2+ was mediated by an activation of the coagulation system with the formation of thrombin.