Gray I P, Siddle K, Docherty K, Frank B H, Hales C N
Clin Endocrinol (Oxf). 1984 Jul;21(1):43-7. doi: 10.1111/j.1365-2265.1984.tb00134.x.
The immunoreactivity of an extracted pancreatic human proinsulin standard in an indirect immunoradiometric assay was found to be at least one hundred times higher than that of biosynthetic human proinsulin. Limited tryptic digestion of the biosynthetic proinsulin increased its immunoreactivity in the assay and this was attributed to the production of partially cleaved proinsulin molecules which still retained the C-peptide moeity. This inference was confirmed by the finding that pure samples of 65/A1 and 32/33 split proinsulins reacted in the assay very similarly to the pancreatic proinsulin standard. The implications of these results are that the immunoassays of proinsulin using antisera to C-peptide may recognise the intact proinsulin molecule very poorly, if at all, and that the 'proinsulin' measured by such assays of human serum may be largely if not entirely intermediates of proinsulin cleavage.
在间接免疫放射分析中，发现提取的人胰岛素原标准品的免疫反应性比生物合成人胰岛素原至少高100倍。对生物合成胰岛素原进行有限的胰蛋白酶消化可增加其在分析中的免疫反应性，这归因于产生了仍保留C肽部分的部分裂解胰岛素原分子。65/A1和32/33裂解胰岛素原的纯样品在分析中的反应与胰腺胰岛素原标准品非常相似，这一发现证实了这一推断。这些结果的意义在于，使用抗C肽抗血清进行胰岛素原免疫分析可能很难识别完整的胰岛素原分子，即便能识别也很差，而且通过此类人血清分析所测得的“胰岛素原”可能大部分（如果不是全部）是胰岛素原裂解的中间体。
