Hildebrand A
Institut für Medizinische Mikrobiologie, Justus-Liebig-Universität, Giessen, F.R.G.
Biochem Biophys Res Commun. 1989 Mar 15;159(2):799-806. doi: 10.1016/0006-291x(89)90065-x.
Beta-Endorphin has been reported to specifically interact with SC5b-9 complement complexes via non-opioid binding sites. Covalent cross-linking of [125I]beta H-endorphin to SC5b-9 and analysis of the cross-linking products by gel electrophoresis and subsequent autoradiography revealed a single specifically labelled species which was identical with the S protein subunit of the complement complex. In contrast to SC5b-9, no cross-linking of labelled beta-endorphin to subunits of C5b-9(m) could be observed, indicating that beta-endorphin binding to SC5b-9 was mediated exclusively via S protein. Beta-Endorphin binding to SC5b-9 was compared with binding to purified S protein. Whereas beta-endorphin binding to purified S protein was only modest, complex formation of S protein with complement proteins led to a strong increase in beta-endorphin-binding site concentration, compatible with the exposure of primarily cryptic beta-endorphin-binding sites on S protein.
据报道，β-内啡肽可通过非阿片类结合位点与SC5b-9补体复合物特异性相互作用。将[125I]βH-内啡肽与SC5b-9进行共价交联，并通过凝胶电泳和随后的放射自显影分析交联产物，结果显示有一个单一的特异性标记物，它与补体复合物的S蛋白亚基相同。与SC5b-9不同，未观察到标记的β-内啡肽与C5b-9(m)亚基的交联，这表明β-内啡肽与SC5b-9的结合仅通过S蛋白介导。将β-内啡肽与SC5b-9的结合与它与纯化的S蛋白的结合进行了比较。虽然β-内啡肽与纯化的S蛋白的结合程度一般，但S蛋白与补体蛋白形成复合物会导致β-内啡肽结合位点浓度大幅增加，这与S蛋白上原本隐藏的β-内啡肽结合位点的暴露情况相符。
