Original Articles
Paweena Pradniwat and Ponlapat
Abstract
Snakebites are the important global public health problem. Viper bites cause a low fibrinogen level and a systemic hemorrhage in human victims. Thrombin-like enzymes (TLEs) that degrade fibrinogen are the key molecules contributing to this viper-induced coagulopathy. Furthermore, these venom proteins have potentials to be novel anti-thrombotic agents. In this study, we expressed a TLE from green pit viper (Trimeresurus albolabris), GPV-TL1, in Pichia pastoris system and characterized its activities on human fibrinogen and platelets. The recombinant protein migrates as an approximately 31.6 kDa on SDS-PAGE under reducing condition. It released both fibrinopeptide A and fibrinopeptide B from human fibrinogen and showed plasma clotting activity of 233.3 thrombin units/mg. However, there was no platelet-aggregating activity. The recombinant GPV-TL1 could directly digest Aα- and Bβ-chains of plasminogen-free human fibrinogen within 30 minutes and later degrade the fibrinogen γ-chain. Therefore, the GPV-TL1 displayed a strong Aa and Bb fibrinogenolytic activities while presenting a relatively weaker coagulant effect. This information gives us a deeper insight into the pathogenesis of GPV bites. The GPVTL1 should be further investigated for the role in the treatment of thrombosis.