文章基本信息

标题：Covalent crosslinking of human chorionic gonadotropin to its receptor in rat testes
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作者：R V Rebois ; F Omedeo-Sale ; R O Brady 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：4
页码：2086-2089
DOI：10.1073/pnas.78.4.2086
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The bifunctional crosslinking reagents disuccinimidyl suberate and dithiobis(succinimidyl propionate) were used to attach 125I-labeled human chorionic gonadotropin (125I-hCG) covalently to rat testicular membranes. The extent of crosslinking was dependent on time and concentration; routinely, 30% of the specifically bound hormone was covalently linked to the membranes in the presence of 0.5 mM crosslinking reagent when incubated at 25 degrees C for 15 min. Excess unlabeled hCG blocked the crosslinking of 125I-hCG to the membranes. When solubilized with Triton X-100 and analyzed by sucrose density gradient centrifugation, both the native and the crosslinked hormone-receptor complex sedimented with an apparent Mr of 220,000. Thus, the receptor itself would have Mr 180,000. When the crosslinked complex was analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, the predominant species had a Mr of 123,000 and appeared to represent the labeled alpha subunit of hCG covalently linked to a membrane component. The Mr of this receptor component would be 100,000, a value approximately half that of the Triton X-100-solubilized receptor. Thus, the membrane receptor for hCG may consist of a dimer of two binding subunits or a binding subunit associated with one or more additional subunits that might play a coupling or regulatory function.