Ji I, Yoo B Y, Kaltenbach C, Ji T H
J Biol Chem. 1981 Nov 10;256(21):10853-8.
Ovarian granulosa cells have specific receptors for lutropin and human choriogonadotropin (hCG). To investigate the nature of the receptor, several different photo-cross-linkable derivatives of radioiodinated hCG were incubated with porcine granulosa cells and hormone derivative-receptor complexes extracted with 0.5% Triton X-100. The extracted complexes appeared in a single peak on gel permeations and in rat zonal sedimentation studies. The estimated molecular weight was found to be 250,000-370,000 with an associated s value of 7.7 +/- 0.3. When Triton X-100 extracts were examined by gel electrophoresis, the autoradiograph revealed four bands. Three were conspicuous, corresponding for molecular weights of 96,000 +/- 5,000, 76,000 +/- 4,000, and 73,000 +/- 4,000, but a fourth band, corresponding to a molecular weight of 120,000 +/- 6,000, was less well defined. Reducing agents, 20 mM dithiothreitol and 2% beta-mercaptoethanol, acid, and 3 M urea did not affect the production of the bands. Furthermore, the bands once formed were resistant to these agents, indicating 1) covalent nondisulfide bond formation in photoaffinity labeling and 2) noncovalent association of photoaffinity-labeled membrane components with the natural hormone receptor.
卵巢颗粒细胞具有促黄体生成素和人绒毛膜促性腺激素（hCG）的特异性受体。为了研究该受体的性质，将几种不同的放射性碘化hCG的可光交联衍生物与猪颗粒细胞一起孵育，并用0.5% Triton X-100提取激素衍生物-受体复合物。在凝胶渗透和大鼠区带沉降研究中，提取的复合物出现在单个峰中。估计分子量为250,000 - 370,000，相关的s值为7.7±0.3。当通过凝胶电泳检查Triton X-100提取物时，放射自显影片显示出四条带。三条带明显，对应的分子量分别为96,000±5,000、76,000±4,000和73,000±4,000，但第四条带，对应分子量为120,000±6,000，不太清晰。还原剂20 mM二硫苏糖醇和2%β-巯基乙醇、酸和3 M尿素不影响条带的产生。此外，一旦形成的条带对这些试剂具有抗性，这表明1）在光亲和标记中形成了共价非二硫键，以及2）光亲和标记的膜成分与天然激素受体的非共价结合。
