Protease inhibitor in scorpion (Mesobuthus eupeus) venom prolongs the biological activities of the crude venom.
It is hypothesized that protease inhibitors play an essential role in survival of venomous animals through protecting peptide/protein toxins from degradation by proteases in their prey or predators. However, the biological function of protease inhibitors in scorpion venoms remains unknown. In the present study, a trypsin inhibitor was purified and characterized from the venom of scorpion Mesobuthus eupeus, which enhanced the biological activities of crude venom components in mice when injected in combination with crude venom. This protease inhibitor, named MeKTT-1, belonged to Kunitz-type toxins subfamily. Native MeKTT-1 selectively inhibited trypsin with a Kivalue of 130 nmol·L(-1). Furthermore, MeKTT-1 was shown to be a thermo-stable peptide. In animal behavioral tests, MeKTT-1 prolonged the pain behavior induced by scorpion crude venom, suggesting that protease inhibitors in scorpion venom inhibited proteases and protect the functionally important peptide/protein toxins from degradation, consequently keeping them active longer. In conclusion, this was the first experimental evidence about the natural existence of serine protease inhibitor in the venom of scorpion Mesobuthus eupeus, which preserved the activity of venom components, suggests that scorpions may use protease inhibitors for survival.
Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of sciences, Kunming 650223, China; Graduate University of Chinese Academy of Sciences, Beijing 100009, China.
Hakim
H
Ma
Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of sciences, Kunming 650223, China; Graduate University of Chinese Academy of Sciences, Beijing 100009, China.
Tang
T
Xiao-Peng
Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of sciences, Kunming 650223, China; Graduate University of Chinese Academy of Sciences, Beijing 100009, China.
Shi-Long
SL
Yang
Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of sciences, Kunming 650223, China; Joint Laboratory of Natural peptide, University of Science and Technology of China and Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China. Electronic address: lvqm@mail.kiz.ac.cn.
Qiu-Min
QM
Lu
Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of sciences, Kunming 650223, China; Joint Laboratory of Natural peptide, University of Science and Technology of China and Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China. Electronic address: rlai@mail.kiz.ac.cn.
Ren
R
Lai
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D007700:Kinetics; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011480:Protease Inhibitors / Q000737:chemistry* / Q000633:toxicity; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics / Q000633:toxicity; D012605:Scorpions / Q000737:chemistry* / Q000235:genetics; D014357:Trypsin / Q000737:chemistry
D011480:Protease Inhibitors; D012604:Scorpion Venoms; D014357:Trypsin
MeKTT-1; Protease inhibitor; Scorpion Mesobuthus eupeus; Venom