Mittag T W, Massa T
J Pharmacol Exp Ther. 1981 Jul;218(1):27-33.
The interaction of the nicotinic acetylcholine receptor from denervated rat muscle (AChR, solubilized in Triton X-100) and Concanavalin-A (Con-A) was studied by soluble Con-A competing with the binding of AChR to agarose immobilized Con-A, by immuno-precipitation of Con-A-AChR complexes and by inhibition of alpha-bungarotoxin binding to AChR. Results showed that Con-A bound to 85% of all AChR molecules at multiple cooperative binding sites. Con-A caused a partial inhibition of toxin binding to a maximum of 41% of receptors, but only when AChR was first incubated with Con-A before toxin labeling and not when the order was reversed. The blockade of toxin labeling was reversed when the Con-A-AChR complexes were treated with mannose (0.75 M). Receptor-Con-A complexes in which toxin binding was not inhibited showed saturation binding of toxin with a decreased apparent affinity. A sub-population of AChR prepared by affinity purification on Lens Culinaris lectin-agarose columns was 100% inhibited from toxin binding when preincubated with Con-A. We conclude that receptors from denervated rat muscle which bind Con-A (85% of the total AChR) contain two major subpopulations of AChR in the approximate proportions 6:4 that can be distinguished by interactions with lectins having specificity for mannose.
通过可溶性伴刀豆球蛋白A（Con - A）与乙酰胆碱受体（AChR，溶解于Triton X - 100中）竞争其与琼脂糖固定化Con - A的结合、通过免疫沉淀Con - A - AChR复合物以及通过抑制α - 银环蛇毒素与AChR的结合，研究了去神经大鼠肌肉中的烟碱型乙酰胆碱受体（AChR）与伴刀豆球蛋白A（Con - A）的相互作用。结果表明，Con - A在多个协同结合位点与所有AChR分子的85%结合。Con - A对毒素与受体的结合产生部分抑制，最大抑制率达41%，但仅当AChR先与Con - A孵育然后再进行毒素标记时才会出现这种情况，顺序颠倒时则不会。当用甘露糖（0.75 M）处理Con - A - AChR复合物时，毒素标记的阻断作用被逆转。毒素结合未被抑制的受体 - Con - A复合物表现出毒素的饱和结合，但其表观亲和力降低。在扁豆凝集素 - 琼脂糖柱上通过亲和纯化制备的AChR亚群，在与Con - A预孵育后，100%被抑制与毒素结合。我们得出结论，去神经大鼠肌肉中能结合Con - A的受体（占总AChR的85%）包含两个主要的AChR亚群，其大致比例为6:4，可通过与对甘露糖具有特异性的凝集素的相互作用来区分。
