Inhibition of the Thrombin-Fibrinogen Reaction by α2-Macroglobulin, Studied by N-Terminal Analysis

Abstract

SummaryThe influence of α2-macroglobulin on the thrombin-fibrinogen reaction was studied with purified human reagents. The N-terminal changes reflecting fibrinopeptide release was measured.α2-macroglobulin inhibited progressively the release of fibrinopeptides A and B. Fibrin polymerization was not influenced. The amount of fibrin formed depended on thrombin and α2-macroglobulin concentrations. When initial thrombin concentration was below 0.2 NIH units/ml, physiological α2-macroglobulin concentrations reduced fibrin formation. The contribution of α2-macroglobulin to the inhibition of the thrombin-fibrinogen reaction in plasma was evaluated.