A Novel Myotoxin from the Venom of
Trimeresurus mucrosquamatus
XU Tian-Rui, WANG Wan-Yu, MENG Qing-Xiong, HUANG Yu-Hui,LU
Qiu-Ming and XIONG Yu-Liang*
( Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming
650223, China )
Abstract A novel myotoxin, designated
TMPB, was purified from the venom of Trimeresurus mucrosquamatus by
Sephadex G-100 superfine gel chromatography and fast protein liquid
chromatography (FPLC). The N-terminal sequence of 24 amino acid residues was
determined by protein sequencer. The sequence similarities between TMPB and
other two phospholipase A2 (PLA2s) previously purified
from the same venom were 41.7% and 54.2%, respectively, but TMPB showed no
detectable PLA2 hydrolytic activity. Its molecular weight was
estimated to be 16 000 by reducing SDS-PAGE and isoelectric point was
determined to be 9.2 by isoelectric focusing electrophoresis. TMPB exhibited
strong myotoxicity and platelet aggregation inhibiting activity, and the two
activities could all be inhibited by heparin.
Key Words Myotoxin； phospholipase A2； platelet； Trimeresurus
mucrosquamatus； venom
Corresponding author:
Tel, 86-871-5194279; Fax, 86-871-5191823; e-mail, [email protected]