人绒毛膜促性腺激素β亚基酶解片段特性的研究  

Characterization of the Enzymatic Fragments of Human Chorionic Gonadotropin β-subunit

作　　者：周先锁[1] 李伟雄[2] 李平风[1] 杜国光[1] 

机构地区：[1]北京医科大学生物化学教研室 [2]北京医科大学生理教研室

出　　处：《生物化学杂志》1993年第2期200-203,共4页

基　　金：国家自然科学基金

摘　　要：以嗜热菌蛋白酶水解人绒毛膜促性腺激素,亚基(hCG_β),用HPLC分离制备酶解产物。酶解片段经竞爭性放射分析,不能与LH/hCG受体结合,但保留近乎全部hCG_β的免疫反应性.园二色谱分析,与hCG_β比较,酶解片段所含α螺旋减少,β折叠与无规卷曲含量增多。表明hCG_β可能有几个肽段和/或糖链参与hCG受体相互作用;酶解片段中仍含有hCG_β的主要决定簇,该决定簇与hCG_β结合受体的结构有区别。A β-subunit of human chorionic gonadotropin (hCG_β) was degraded by protease-thermolysin. The enzymatic fragments were partially purified by HPLC (TSK-Sil). Competitive radioimmunoassays and radioreceptor binding assays (RIAs & RBAs) were performed. In RBAs, no sign of binding onto Leydig cells' LH/hCG receptors were shown by the fragments up to the concentration of 181.89. μg/mL, while they retain nearly full immunoreactivity of hCG_β in RIAs. Circular dichroic measurements give increased β-sheet, random coil and decreased α- helix con ent of the fragments as compared to that of intact hCG_β, respectively. These results indicate that several sites on hCG_β were needed to react with LH/hCG receptor. However, the main antigenic determinants of hCG_β, which are located far away from the above sites, still exist on the enzymatic fragments of hCG_β.

关 键 词：HCG 亚基 酶解片段 免疫反应性 

分 类 号：R392.1[医药卫生—免疫学]