Desialylation of N-Linked Carbohydrate Chain of Fibrinogen

Acceleration of fibrin polymerization occurs by the cleavage of sialic acids at the nonreducing terminal ends of N-linked carbohydrate chains as well as the cleavage of the entity of carbohydrate chains. In order to characterize and clarify the role of terminal sialic acid in the fibrin polymerization, mixing effects of desialylated fibrinogen with the intact one on the polymerization behavior were investigated by turbidity measurements in the course of polymerization. Marked accelerated fibrin polymerization was observed for the mixing of even a little amount of desialylated fibrinogen. Cleavage of the terminal sialic acid resulted in almost the equivalent accelerating effect to those of the deglycosylated fibrinogen, in which the entity of N-linked carbohydrate chain was cleaved. These results suggest that the terminal sialic acids regulate the fibrin polymerization in an inhibitory manner, and the cleavage of them induces the switchover from the protofibril growth to the lateral aggregation of fibrin polymerization process, resulting in the preferential fibrin polymerization.