Issue Archive

Channel-forming activity at planar lipid bilayer of the membrane active polyptide B form venom of Bungarus Fasciatus

SHI Yu-Liang, WANG Wen-Ping, Zhang Hui, Xu Ke

Shanghai Institute of physiology, Academia Sinica,Shanghai 200031

Abstract

Using planar lipid bilayer formed by lecithin and cholesterol （20 and 5 mg/mlrespectively in N-decane） the channel-forming activity of the membrane activepolypeptidc B（BMAP B） from the venom of Bungarus fasciatus was investigated.Under the existance of a voltage or a salt concentration gradient between two sidesof the bilayer, unit conductance fluctuation and a decrease in steady state resistanceaccompanying BMAP B incorporation and channel formation were observed. Bymeasuring the reversal potential in an asymmetric solution, the selectiviy of theBMAP B-channel was estimated having a value of PK/PCl=1.4. Divalent cations,such as Ba2+, Ca2+ inhibited the channel activity as they did in biomembranes.These data might provide an explanation for the depolarizing effect of the mem-brane active polypeptide on the native membranes.

Key words: bungraus venom;membr aneactive polypeptide;planar lipid bilayer;Ion channel;unit conductance fluctuation;divalent cations

Received: 　　Accepted:

Corresponding author: 　　E-mail:

Citing This Article：

SHI Yu-Liang, WANG Wen-Ping, Zhang Hui, Xu Ke. Channel-forming activity at planar lipid bilayer of the membrane active polyptide B form venom of Bungarus Fasciatus. Acta Physiol Sin 1992; 44 (6): 533-540 (in Chinese with English abstract).