Biopolymers and cell. 1991. Volume 7. № 3. 82 - 89

SEREYSKAYA A. A., SMIRNOVA I. A.

Action of Clotting (α) and Nonclotting (γ) Thrombins on Bovine Fibrinogcn N-Terminal Fragments

Summary

    Bovine fibrinogen N-terminal fragments were hydrolysed by native cc-thrombin and its nonclotting Y-f°rm (with disruptured additional centre for high molecular substrates recognition). It was found that susceptible bond 19—20 of Ace chain is cleaved by cc-thrombin more efficiently than Y'form both in the structure of N-terminal disulfide knot and in the isolated Atx fragment 1—54. This difference disappears as a result of peptide bonds splitting due to Ace Trp36 and Trp44 modification. The rate of a-thrombin hydrolysis of modified substrates is lowered significantly ad reached the ythrombin level. The data presented here establish that 1) the specific site complementary to thrombin additional recognition centre is localized wiihinn the sequence 37—54 of bovine fibrinogen Act chain; 2) interactions between fibrinogen and thrombin recognition sites arc necessary for effective 19—20 bond hydrolysis.