BmK AS在大鼠脑和蟑螂神经索突触体上的药理结合特性  

Characteristics of BmK AS Binding to Rat Brain and Cockroach Nerve Cord Synaptosomes

作　　者：李亚军[1] 刘艳 吉永华[1] 

机构地区：[1]中国科学院上海生理研究所上海生命科学研究中心,上海200031

出　　处：《生物化学与生物物理学报》1999年第5期604-606,共3页

摘　　要：用 Ｉ Ｎ Ｄ Ｏ Ｇ Ｅ Ｎ 法对一个新型东亚钳蝎活性多肽 Ｂｍ Ｋ Ａ Ｓ 进行了１２５ Ｉ标记。分别在哺乳动物和昆虫标本上观察了标记物的药理结合特性。结果表明 Ｂｍ Ｋ Ａ Ｓ 在大鼠脑突触体标本上有单一非协同结合位点， 其平衡解离常数 Ｋｄ 与最大结合容量 Ｂｍａｘ 分别为１ ．４９ ｎｍｏｌ／ Ｌ 和１ ．３９ ｎｍｏｌ／ｇ 。此外， Ｂｍ Ｋ Ａ Ｓ 在蟑螂神经索突触体标本同样也只有单一非协同结合位点， 其平衡解离常数 Ｋｄ 与最大结合容量 Ｂｍａｘ 分别为０ ．７９ ｎｍｏｌ／ Ｌ 和６ ．６０ ｎｍｏｌ／ｇ 。结果提示， Ｂｍ Ｋ Ａ Ｓ类蝎神经毒素在哺乳动物和昆虫兴奋性细胞膜上存在着特异的靶受体。BmK AS, one novel neurotoxic polypeptide from Chinese scorpion Buthus martensi Karsch was labeled by 125 I 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 ( K d=1.49 nmol/L) and low capacity ( B max =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 ( K d=0.79 nmol/L) and low capacity ( B max =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.

关 键 词：蝎神经毒素 钠通道 碘125 结合特性 脑 蟑螂 

分 类 号：R966[医药卫生—药理学]