The Characterizations and Blocking Effects on Ito of Rat Ventricular Myocyte of New Minipeptides from Buthus martensi Karsch.
Two minipeptides (BmP02 and BmP03) with M.W. 2.950 kD and 2.935 kD determined respectively by electrospray ionization mass spectrum, were purified from the venom of Buthus martensi Karsch by an opportune procedure on cation-exchange column chromatography and repeated HPLC. The amino acid sequence of BmP02 had been determined. Using whole-cell patch clamp, BmP02 was studied on rat ventricular myocyte. The results showed that BmP02 inhibited the transient outward current (Ito) of rat ventricular myocytes with partial recovery after washout (n=5) and its inhibition had concentration dependence and voltage independence. Further study showed that BmP02 affected both the inactivation and recovery kinetics, but not activation kinetics of Ito channel.
Tong
Qing-Chun
QC
Shanghai Institute of Physiology, the Chinese Academy of Sciences, Shanghai 200031, China. yhji@server.shcnc.ac.cn
Zhang
Yi
Y
Zhou
Zhao-Nian
ZN
Ji
Yong-Hua
YH