title: [Channel-forming activity at planar lipid bilayer of the membrane active polypeptide B form venom of Bungarus fasciatus].
abstract: Using planar lipid bilayer formed by lecithin and cholesterol (20 and 5 mg/ml respectively in N-decane) the channel-forming activity of the membrane active polypeptide B(BMAP B) from the venom of Bungarus fasciatus was investigated. Under the existence of a voltage or a salt concentration gradient between two sides of the bilayer, unit conductance fluctuation and a decrease in steady state resistance accompanying BMAP B incorporation and channel formation were observed. By measuring the reversal potential in an asymmetric solution, the selectivity of the BMAP B-channel was estimated having a value of PK/PC1 = 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 membrane active polypeptide on the native membranes.
authors.affiliation: Shanghai Institute of physiology, Academia Sinica.
authors.forename: Y L
authors.initials: YL
authors.lastname: Shi
authors.forename: W P
authors.initials: WP
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: K
authors.initials: K
authors.lastname: Xu
mesh_terms: D000818:Animals; D002038:Bungarotoxins / Q000737:chemistry*; D002413:Cations, Divalent; D002784:Cholesterol; D004179:Cobra Cardiotoxin Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines
chemical_list: D002038:Bungarotoxins; D002413:Cations, Divalent; D004179:Cobra Cardiotoxin Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D002784:Cholesterol