Snake venom thrombin-like enzymes

Abstract

Thrombin-like enzymes (TLEs) are serine proteases, found mainly in pit viper venoms that induce coagulopathy. Hypofibrinogenemia is a usual result of fibrinogen degradation by TLEs. Viper-derived TLEs are promising as diagnostic or therapeutic agents and research tools to reveal the fibrinopeptide release mechanisms from fibrinogen. The TLEs have highly conserved structures, such as catalytic triads and six disulfide bridges, yet very diverse activities through accelerated evolution mechanisms. Glycosylation of the molecules may provide protein stability and contribute to some activities of the enzymes. In contrast to thrombin, which contains well-defined anion-binding exosites 1 and 2, the presence of substrate recognition sites on TLEs is unclear. Further protein structure-function analysis is still required.

• Fibrinogen
• FRE
• hypofibrinogenemia
• serine protease
• serine proteinase
• TLE

Acknowledgements

The authors would like to thank the Biomedical Science, Interdisciplinary Program, Graduate School, Chulalongkorn University, and Thai Research Fund and The Commission on Higher Education.