Bertagna X, Camus F, Lenne F, Girard F, Luton J P
Centre de Recherche sur les Maladies Endocriniennes, Hôpital Cochin, Paris, France.
Mol Endocrinol. 1988 Nov;2(11):1108-14. doi: 10.1210/mend-2-11-1108.
The human (h) POMC gene sequence predicts a 30 amino acid joining peptide (JP) separating the N-terminal fragment [POMC(1-76) or hNT] and ACTH within their common precursor. We used an anti-serum directed against the amidated COOH-terminal end of mouse JP to develop a RIA for the predicted hJP molecule. Immunoreactive JP was detected in tissue extracts from human normal pituitary, ACTH-secreting pituitary- and nonpituitary tumors, and in plasma from patients with ACTH hypersecretory syndromes. Its molar concentration was of the same order of magnitude as, and correlated with, that of the other POMC peptides. Gel exclusion chromatography in 1% formic acid and 6 M guanidine-HCl revealed a predominant immunoreactive material with an apparent mol wt of ca. 6000. After reduction with dithiothreitol this material was recovered in an elution volume identical to that of purified hJP and corresponding to a mol wt of ca. 3000. These data show that POMC processing generates a COOH terminally amidated hJP predominantly secreted as a homodimer, probably through disulfide bonding between the single Cys9 residue of two molecules.
人类（h）阿黑皮素原（POMC）基因序列预测，在其共同前体中，一个30个氨基酸的连接肽（JP）将N端片段[POMC(1 - 76)或hNT]与促肾上腺皮质激素（ACTH）分隔开来。我们使用针对小鼠JP酰胺化COOH末端的抗血清，开发了一种针对预测的hJP分子的放射免疫分析方法（RIA）。在来自人类正常垂体、分泌ACTH的垂体和非垂体肿瘤的组织提取物中，以及在ACTH分泌过多综合征患者的血浆中，检测到了免疫反应性JP。其摩尔浓度与其他POMC肽的摩尔浓度处于相同数量级且相关。在1%甲酸和6 M盐酸胍中进行凝胶排阻色谱分析，显示出一种主要的免疫反应性物质，其表观分子量约为6000。用二硫苏糖醇还原后，该物质在与纯化的hJP相同的洗脱体积中回收，对应分子量约为3000。这些数据表明，POMC加工产生了一种COOH末端酰胺化的hJP，主要以同二聚体形式分泌，可能是通过两个分子的单个Cys9残基之间的二硫键结合。
