THE CATION SENSITIVITY OF THE ACETYLCHOLINE RECEPTOR FROM TORPEDO CALIFORNICA
THE CATION SENSITIVITY OF THE ACETYLCHOLINE RECEPTOR FROM TORPEDO CALIFORNICA
复制标题
加州鱼雷乙酰胆碱受体的阳离子敏感性
作者：
J. Schmidt;M. Raftery
研究了不同阳离子和胆碱能配体对α-银环蛇毒素-乙酰胆碱受体复合体形成速率的影响。在2·5·10−6M乙酰乙醇胺存在下，反应速率降至初始速率的一半。接近用平衡透析法测得的ACh的Kd值。大多数一价阳离子的抑制常数约为5 mM，而二价阳离子的抑制常数为0.05~0.2 mM。还研究了毒素-受体复合体的形成速度和程度与氢离子浓度的关系，在pH为7·5时形成速率最大，当质子化时，pk约为6的基团抑制了毒素与受体的结合。
—The effects of various cations and cholinergic ligands on the rate of α‐bungarotoxin‐acetylcholine receptor complex formation has been studied by means of a DEAE‐cellulose disk assay technique. The reaction rate is reduced to one half the initial rate in the presence of 2·5 · 10−6m acetyleholine. a value close to the observed KD of ACh measured by equilibrium dialysis. Inhibition constants of about 5 mM were obtained for most monovalent cations whereas divalent cations gave inhibition constants of 0·05‐0·2 mm. The rate and extent of toxin‐receptor complex formation was also investigated as a function of hydrogen ion concentration; the rate of formation reaches a maximum at pH 7·5 and a group with a pK about 6 inhibits toxin binding to the receptor when protonated.