Characteristics of BmK AS Binding to Rat
Brain and Cockroach Nerve Cord Synaptosomes
LI Ya-Jun, LIU Yan and JI Yong-Hua*
( Shanghai Institute of Physiology, Shanghai Research Center of Life
sciences,the Chinese Academy of Sciences, Shanghai 200031,China )
Abstract BmK AS, one novel neurotoxic
polypeptide from Chinese scorpion Buthus martensi Karsch was labeled
by 125I with INDOGEN method. Iododerivative was used in binding
experiments on mammal and insect synaptosomes. BmK AS binds specifically to a
single class of non-interacting binding sites with high affinity (Kd=1.49
nmol/L) and low capacity (Bmax=1.39 nmol/g) on rat brain
synaptosomes. Likewise, BmK AS also binds specifically to a single class of non-interacting
binding sites with high affinity (Kd=0.79 nmol/L) and low
capacity (Bmax=6.60 nmol/g) on cockroach nerve cord
synaptosomes. It indicates that there are special target receptors for BmK AS
type scorpion neurotoxins on both mammal and insect excitable cell membranes.
Key Words scorpion neurotoxins； sodium channels； 125I； binding experiments
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