Srikant C B, Patel Y C
Biochem Biophys Res Commun. 1986 Sep 14;139(2):757-62. doi: 10.1016/s0006-291x(86)80055-9.
Adrenocortical somatostatin receptors have been shown to interact with somatostatin-14 (S-14) and somatostatin-28 (S-28). To determine whether these peptides interact with the same or different receptor proteins, we chemically cross-linked these receptors using disuccinimidyl suberate to radioligands prepared from tyrosinated S-14 and S-28 analogs. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and subsequent autoradiography of [125I-Tyr11] S-14 and [Leu8, D-Trp22, 125I-Tyr25] S-28 cross-linked to their binding sites following solubilization in the presence of 50 mM DTT revealed the presence of a single labelled protein of Mr = 200,000. When the cross-linked material was treated under non-reducing conditions, this band was not observed. Furthermore, addition of excess S-14 and S-28 at the time of binding inhibited the incorporation of both radioligands into the receptor protein. These results demonstrate that adrenocortical membrane receptors for somatostatin contain a single receptor protein sub-unit or sub-units of identical size which interact with both S-14 and S-28.
肾上腺皮质生长抑素受体已被证明可与生长抑素-14（S-14）和生长抑素-28（S-28）相互作用。为了确定这些肽是否与相同或不同的受体蛋白相互作用，我们使用辛二酸二琥珀酰亚胺酯将这些受体化学交联至由酪氨酸化的S-14和S-28类似物制备的放射性配体上。在50 mM二硫苏糖醇存在下溶解后，对交联至其结合位点的[125I-Tyr11] S-14和[Leu8, D-Trp22, 125I-Tyr25] S-28进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳及随后的放射自显影，结果显示存在一种单一的标记蛋白，其相对分子质量为200,000。当在非还原条件下处理交联材料时，未观察到该条带。此外，在结合时加入过量的S-14和S-28可抑制两种放射性配体掺入受体蛋白。这些结果表明，肾上腺皮质生长抑素膜受体含有一个单一的受体蛋白亚基或大小相同的亚基，它们与S-14和S-28均相互作用。
