Snell C R, Smyth D G
J Biol Chem. 1975 Aug 25;250(16):6291-5.
Empirical analysis of the primary structures of 10 mammalian C-peptides has indicated a conservation of conformation. The positioning of the C-peptide in the proinsulin molecule is essentially defined by the proposed secondary structure, the covalent connection to the A1 and B30 residues of insulin and the requirement that C-peptide lies against the exposed surface of the insulin hexamer, allowing a three-dimensional structure for proinsulin to be predicted. Conserved residues in the C-peptide are proximate to residues in insulin that are also conserved, suggesting that interactions between these residues are highly probable. Residues in insulin thought to be important for biological activity are principally those that interact with the C-peptide residues. The role of the C-peptide region in proinsulin in preventing expression of insulin activity and for nucleation of the folding of the prohormone are discussed.
对10种哺乳动物C肽一级结构的实证分析表明其构象具有保守性。C肽在胰岛素原分子中的定位基本上由所提出的二级结构、与胰岛素A1和B30残基的共价连接以及C肽位于胰岛素六聚体暴露表面的要求所确定，从而使得胰岛素原的三维结构得以预测。C肽中的保守残基靠近胰岛素中同样保守的残基，这表明这些残基之间很可能存在相互作用。胰岛素中被认为对生物活性很重要的残基主要是那些与C肽残基相互作用的残基。本文讨论了胰岛素原中C肽区域在阻止胰岛素活性表达以及前激素折叠成核过程中的作用。
