Synthesis of a fragment of human parathyroid hormore, hPTH-(44-68).
Synthesis of a fragment of human parathyroid hormore, hPTH-(44-68).
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人甲状旁腺激素片段 hPTH-(44-68) 的合成。
DOI：
10.1021/jm00221a017
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发表时间：
1977
影响因子：
7.3
通讯作者：
J. Potts
中科院分区：
文献类型：
--
作者：
M. Rosenblatt;H. Keutmann;G. Tregear;J. Potts
用固相法合成了人甲状旁腺激素（hPTH-（44-68））的内部区域的25个氨基酸的肽。合成该区域以获得针对PTH的羧基末端三分之二的抗血清，并确定除了氨基末端三分之一之外的激素部分是否参与完整激素中的生物效应。由于人甲状旁腺激素与牛同源物在三个位置不同，因此制备了人片段。对合成肽以及副产物进行了详细的化学分析。通过氨基酸组成、薄层色谱法、薄层电泳和聚丙烯酰胺凝胶等电聚焦评价均匀性。进行序列分析以检测和定量含有缺失的错误肽。在合成过程中形成了几种较短链长的肽。在负责产生副产物的机制中，有由于空间不可及性导致的过早链终止和谷氨酸环化形成焦谷氨酰肽。通过这些机制形成的副产物可能是序列依赖性的。合成的hPTH-（44-68）在体外和体内均缺乏激动剂活性，并且在体外不抑制天然甲状旁腺激素，表明该分子的该区域缺乏受体结合。区域44-685的结构分析显示，人与牛激素（bPTH）在位置46、47和64处不同，其中丙氨酸取代甘氨酸，甘氨酸取代丝氨酸，谷氨酸取代谷氨酰胺发生在这些相应位点的每一个（图1）。这种合成片段可用于尝试产生针对人激素的区域特异性抗血清。采用固相法合成hPTH-（44-68）。通过薄层层析、薄层电泳、氨基酸组成、聚丙烯酰胺凝胶等电聚焦和Edman序列分析检测含有缺失的错误肽，将所需肽纯化至均一。合成过程还产生了较短链长的副产物，分别分离和鉴定，这表明分子中有几个不连续的区域发生副反应。评价合成的hPTH-（44-68）的体外和体内生物活性以及可能的激素拮抗作用。
A 25 amino acid peptide representing an internal region of human parathyroid hormone, hPTH-(44-68), was synthesized by the solid-phase method. This region was synthesized to obtain antisera against the carboxy-terminal two-thirds of PTH and to determine whether portions of the hormone other than the amino-terminal one-third participate in biologic effects resident in the intact hormone. Because human parathyroid hormone differs from the bovine homologue at three positions, the human fragment was prepared. Detailed chemical analysis of the synthetic peptide as well as the side products was performed. Homogeneity was evaluated by amino acid composition, thin-layer chromatography, thin-layer electrophoresis, and polyacrylamide-gel isoelectric focusing. Sequence analysis was performed to detect and quantitate deletion-containing error peptides. Several shorter chain length peptides formed during synthesis. Among the mechanisms responsible for generation of side products are premature chain termination due to steric inaccessibility and cyclizationof glutamic acid to form pyroglutamyl peptides. Formation of side products by these mechanisms may be sequence dependent. Synthetic hPTH-(44-68) lacked agonist activity in vitro and in vivo and does not inhibit native parathyroid hormone in vitro, indicating lack of receptor binding by this region'f the molecule.Determination of a large portion of the sequence of human parathyroid hormone (hPTH), 14 an 84 amino acid peptide, has made possiblethe synthesis of a fragment representing the midregion of the hormone. Structural analysis of the region 44-685 showed the human differs from bovine hormone (bPTH) at positions 46, 47, and 64, where a substitution of alanine for glycine, glycine for serine, and glutamic acid for glutamine occurs at each of these respective sites (Figure 1). Such a synthetic fragment could be used in an attempt to generate re-gion-specific antisera for the human hormone. The sol-id-phase method was used to synthesize hPTH-(44-68). The desired peptide was purified to homogeneity as as-sessed by thin-layer chromatography, thin-layer electrophoresis, amino acid composition, polyacrylamide-gel isoelectric focusing, and Edman sequence analysis for detection of deletion-containing error peptides. The synthetic process also produced shorter chain length side products, separately isolated and identified, that indicate several discrete regions of the molecule where side reac-tions occur. The synthetic hPTH-(44-68) was evaluated for biologic activity in vitro and in vivo and for possible hormonal antagonism.