Human thrombin receptors are insensitive to thrombin-like snake venom enzymes

Y. Shimohigashi, T. Nose, M. Ohno, Y. Ogino, T. Costa

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1 Citation (Scopus)


Thrombin-like snake venoms enzymes, flavoxobin, and okinaxobin I isolated from Trimeresurus flavoviridis and Trimeresurus okinavensis, respectively, were examined in SH-EP cells and evaluated whether or not they can activate human thrombin receptors. Flavoxobin was almost completely inactive in both assays for phosphoinositide turnover and DNA synthesis. In contrast, okinaxobin I stimulated phosphoinositide turnover in a dose dependent manner, but considerably weakly. The EC50 value was about 100 nM, which was 4,000 times larger than that of α-thrombin. This stimulation was not inhibited by hirudin, an effective inhibitor of α-thrombin. Okinaxobin I also induced a very weak stimulation of DNA synthesis. These results suggest that thrombin-like snake venom enzymes interact with human thrombin receptors in inefficient ways. Weak interactions of the enzymes with thrombin receptor and inhibitor were ascribed to the incomplete formation of a lysine-cation cluster necessary for electrostatic molecular recognition.

Original languageEnglish
Pages (from-to)415-421
Number of pages7
JournalBiochemistry and Molecular Biology International
Issue number2
Publication statusPublished - 1995

All Science Journal Classification (ASJC) codes

  • Genetics
  • Molecular Biology
  • Biochemistry


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