Nagahama M, Sakurai J
Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan.
Infect Immun. 1992 Mar;60(3):1237-40. doi: 10.1128/iai.60.3.1237-1240.1992.
125I-epsilon-toxin showed high affinity to rat brain homogenates and synaptosomal membrane fractions, having single binding phases with dissociation constants (Kds) of 2.5 and 3.3 nM, respectively. Treatment of synaptosomal membrane fractions with pronase and neuraminidase lowered the binding of the labeled toxin, whereas treatment with trypsin and phospholipase C did not. Heating of the fractions resulted in a decrease in the binding of the toxin. These data suggest that interaction of epsilon-toxin with cell membranes in the brain is facilitated by a sialoglycoprotein. On the other hand, treatment of the membrane fractions with lipase resulted in complete loss of binding, suggesting that the interaction may require an appropriate lipid environment. These data suggest the presence of specific binding sites in brain tissue for epsilon-toxin.
125I-ε毒素对大鼠脑匀浆和突触体膜组分显示出高亲和力，具有单一结合阶段，解离常数（Kd）分别为2.5和3.3 nM。用链霉蛋白酶和神经氨酸酶处理突触体膜组分降低了标记毒素的结合，而用胰蛋白酶和磷脂酶C处理则没有。加热这些组分导致毒素结合减少。这些数据表明，唾液酸糖蛋白促进了ε毒素与脑细胞膜的相互作用。另一方面，用脂肪酶处理膜组分导致结合完全丧失，表明这种相互作用可能需要适当的脂质环境。这些数据表明脑组织中存在ε毒素的特异性结合位点。
