Bee venom is a rich source of pharmacologically active substances. In this study, we characterized a B. terrestris venom Kunitz-type serine protease inhibitor (Bt-KTI). Bt-KTI consists of two exons encoding 82-amino acids (aa), including a predicted 24-aa signal peptide and a 58-aa mature peptide. Recombinant Bt-KTI was expressed as a 6.5-kDa peptide in baculovirus-infected insect cells. Bt-KTI showed no detectable inhibitory effect on factor Xa, thrombin, or tissue plasminogen activator. In contrast, Bt-KTI strongly inhibited plasmin, indicating that it acts as a plasmin inhibitor. The electrophoretic mobility shift assay showed that Bt-KTI binds to plasmin, indicating the formation of a plasmin-Bt-KTI complex. These results demonstrate that Bt-KTI acts as an antifibrinolytic agent, suggesting a role for Bt-KTI as an anti-bleeding agent.

• Yuling Qiu(College of Natural Resources and Life Science, Dong-A University)
• Kwang Sik Lee(College of Natural Resources and Life Science, Dong-A University)
• Hyung Joo Yoon(Department of Agricultural Biology, National Academy of Agricultural Science)
• Byung Rae Jin(College of Natural Resources and Life Science, Dong-A University)