Production and functional characteristics of a novel hirudin variant with better anticoagulant activities than bivalirudin.

Current antithrombotic therapies face dual constraints of bleeding complications and monitoring requirements. Although natural hirudin provides targeted thrombin inhibition, its clinical adoption is hindered by sourcing limitations. This study developed a recombinant hirudin variant HMg (rHMg) with enhanced anticoagulant activity through genetic engineering and established cost-effective large-scale production methods. The synthesised HMg gene was expressed in E. coli BL21 via a pET vector plasmid, followed by nickel-affinity purification. Systematic evaluations demonstrated rHMg's antithrombin activity of 9573 ATU/mg, dose-dependent prolongation of APTT/PT/TT. It has superior thrombin inhibition with the IC₅₀ and K_i values were 2.8 and 0.323 nM respectively compared to FDA approved drug bivalirudin (p < 0.001). The high-yield prokaryotic expression of rHMg with enhanced anticoagulant efficacy provides a novel strategy for developing affordable antithrombotic drugs, showing significant potential for cardiovascular disease management.