Ruoho A E, Hall C C, Rashidbaigi A
Fed Proc. 1983 Aug;42(11):2837-41.
Radioactive photoaffinity labels have been used to probe the cardiac glycoside-binding site of Na,K-ATPase and the catecholamine-binding site of the beta-adrenergic receptor. For the Na,K-ATPase, a systematic positioning of the photoactive group on the first, second, and third digitoxoses of digitoxin showed that the specific radioactivity in the alpha subunit decreased 5- to 20-fold as the photoactive group was extended further away from the steroid nucleus, whereas the beta subunit is positioned very close to the alpha subunit in the region of the cardiac glycoside-binding site. For the beta-adrenergic receptor, a new class of orthoiodophenylazide derivatives of pindolol was prepared with carrier-free 125I. Photolysis of the beta-adrenergic receptor of duck, turkey, pigeon, and frog erythrocyte membrane with one of these compounds (iodoazidobenzylpindolol) allowed identification of the receptor polypeptides. It was found that the size of the polypeptides and the number of polypeptides varied.
放射性光亲和标记已被用于探测钠钾-ATP酶的强心苷结合位点和β-肾上腺素能受体的儿茶酚胺结合位点。对于钠钾-ATP酶，将光活性基团系统地定位在洋地黄毒苷的第一、第二和第三位洋地黄毒糖上，结果显示，随着光活性基团远离甾体核，α亚基中的比放射性降低了5至20倍，而在强心苷结合位点区域，β亚基与α亚基的位置非常接近。对于β-肾上腺素能受体，制备了一类新的用无载体125I标记的吲哚洛尔的邻碘苯叠氮衍生物。用其中一种化合物（碘叠氮苄基吲哚洛尔）对鸭、火鸡、鸽子和青蛙红细胞膜的β-肾上腺素能受体进行光解，从而鉴定出受体多肽。结果发现，多肽的大小和多肽的数量各不相同。
