Iwai M, Yokoyama H, Yamada H, Niwa M, Kobayashi M
Marine Technical College, Faculty of Liberal Arts and Science, Ashiya, Hyogo, Japan.
Chem Pharm Bull (Tokyo). 2000 Sep;48(9):1304-9. doi: 10.1248/cpb.48.1304.
Insulin-like growth factor I (IGF-I or somatomedin C) is a serum polypeptide with three intramolecular disulfide bonds. In the course of synthesis by the recombinant DNA method, three disulfide bond isomers, all of which have Cys18-Cys61 with three combinations of two disulfide bonds formed by Cys6, Cys47, Cys48 and Cys52, were identified. Natural type, isomer II, was proved to have a Cys6-Cys48, Cys18-Cys61, Cys47-Cys52 disulfide bond system. Now, the fourth isomer, isomer V which doesn't have Cys18-Cys61 disulfide, has been isolated, and its novel disulfide bond linkage system was identified by a chemical synthetic method. The supposed conformation constrained in 3D structure for isomer V would be discussed for its biological activity.
胰岛素样生长因子I（IGF-I或生长调节素C）是一种具有三个分子内二硫键的血清多肽。在用重组DNA方法合成的过程中，鉴定出了三种二硫键异构体，它们均具有Cys18-Cys61，且由Cys6、Cys47、Cys48和Cys52形成的两个二硫键有三种组合。天然型异构体II被证明具有Cys6-Cys48、Cys18-Cys61、Cys47-Cys52二硫键系统。现在，已分离出第四种异构体——不具有Cys18-Cys61二硫键的异构体V，并通过化学合成方法鉴定了其新的二硫键连接系统。将讨论异构体V在三维结构中假定的构象对其生物活性的影响。
