Lukas R J
Biochemistry. 1984 Mar 13;23(6):1160-4. doi: 10.1021/bi00301a020.
The curaremimetic neurotoxin, alpha-bungarotoxin, is shown to interact with two classes of binding sites on rat brain crude mitochondrial fraction membranes. Toxin binding sites are characterized by descriptive, preequilibrium dissociation constants of about 5 and 400 nM. There are at least as many low-affinity toxin binding sites as high-affinity sites. The existence of low- and high-affinity sites is confirmed by experiments with native toxin. Low- and high-affinity toxin binding sites are copurified as judged by sedimentation velocity and density gradient analysis, consistent with the presence of low- and high-affinity toxin binding sites on the same subcellular membrane fragments. The results may offer an explanation for the relatively low antagonistic potency of curaremimetic neurotoxins at acetylcholine-sensitive sites in the vertebrate central nervous system.
箭毒样神经毒素α-银环蛇毒素被证明可与大鼠脑粗线粒体部分膜上的两类结合位点相互作用。毒素结合位点的特征在于描述性的预平衡解离常数，约为5和400 nM。低亲和力毒素结合位点的数量至少与高亲和力位点一样多。天然毒素实验证实了低亲和力和高亲和力位点的存在。通过沉降速度和密度梯度分析判断，低亲和力和高亲和力毒素结合位点可共同纯化，这与同一亚细胞膜片段上存在低亲和力和高亲和力毒素结合位点一致。这些结果可能为箭毒样神经毒素在脊椎动物中枢神经系统中对乙酰胆碱敏感位点的相对较低拮抗效力提供一种解释。
