Glucagon carboxyl-terminal derivatives: preparation, purification, and characterization.
Glucagon carboxyl-terminal derivatives: preparation, purification, and characterization.
复制标题
胰高血糖素羧基末端衍生物：制备、纯化和表征。
DOI：
10.1021/bi00534a020
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发表时间：
1982
期刊：
影响因子：
2.9
通讯作者：
Gurd,RS
中科院分区：
文献类型：
--
作者：
England,RD;Jones,BN;Flanders,KC;Coolican,SA;Rothgeb,TM;Gurd,RS
Richard D. England, Barry N. Jones, 1 Kathleen Corey Flanders, Sharon A. Coolican， T. Michael Rothgeb，§和Ruth S. Gurd**摘要：采用化学和酶促的方法，在激素受体结合的重要羧基末端修饰了7种胰高血糖素衍生物：[des-Asn28， Thr29]（同型丝氨酸内酯27）胰高血糖素、[des-Asn28， Thr29]（同型丝氨酸27）胰高血糖素、（5′-甲基- met27）胰高血糖素、[des-Thr29]（s-甲基- met27）胰高血糖素、[des-Asn28， Thr29]（s-甲基- met27）胰高血糖素和[des-Asn28， Thr29]（s-甲基- met27）胰高血糖素。这些衍生物的分离率高，纯化程度高，并进行了化学表征。所有被发现是天然胰高血糖素的充分激动剂。用新方法制备的单[125I]碘胰高血糖素置换评价其结合亲和力。结合与生物活性密切相关，表明大多数修饰对胰高血糖素的相对结合亲和力和相对生物学效力的影响程度相当。在稀酸中测量环状二色性(胰高血糖素是一种由29个氨基酸组成的激素，因其在腺苷酸环化酶的激活（Rodbell, 1980）和燃料稳态的维持中发挥关键作用，并可能参与糖尿病的发病机制（Unger & Orci, 1981）。最近的研究兴趣越来越多地集中在各种修饰衍生物的开发上，以探索参与胰高血糖作用的分子机制，并寻找临床上有用的激素拮抗剂（Bregman等，1980）。从这些大量的研究中可以得出的一般结论是，几乎整个分子都参与了受体识别过程，并且基本上整个序列是激素活性充分表达所必需的（Epand et al., 1981）。然而，亲脂羧基末端区域似乎在作用机制中没有必要的功能，可能仅对激素的高受体亲和力起重要作用（Wright et al., 1978; Hruby et al., 1981）。有研究表明，受体结合涉及胰高血糖素的螺旋共形体，通过涉及分子羧基末端区域残基的疏水相互作用在受体上诱导或稳定（Sasaki et al., 1975）。疏水的、有利于螺旋的蛋氨酸残位27被认为对受体结合特别重要，因为它似乎促进了胰高血糖素中螺旋的形成，并且胰高血糖素衍生物呈现螺旋构象的能力似乎与其受体相关
Richard D. England, Barry N. Jones, 1 Kathleen Corey Flanders, Sharon A. Coolican, T. Michael Rothgeb, § and Ruth S. Gurd** abstract: Chemical and enzymatic methodshave been used to prepare the following series of seven glucagon derivatives modified in the carboxyl-terminal region important for hormone-receptor binding:[des-Asn28, Thr29](homoserine lactone27) glucagon,[des-Asn28, Thr29](homoserine27) glucagon,(5'-methyl-Met27) glucagon,[des-Thr29](S-methyl-Met27)-glucagon,[des-Thr29] glucagon,[des-Asn28, Thr29](S-methyl-Met27) glucagon, and [des-Asn28, Thr29] glucagon. The deriv-atives were isolated in high yield, extensively purified, and chemically characterized. All were found to be full agonists of native glucagon. Binding affinity was evaluated by dis-placement of mono [125I] iodoglucagon prepared by new methods. Binding and biological activities closely correlated, indicating that most modifications affected the relative binding affinity and relative biological potency of glucagon to a com-parable extent. Circular dichroism measured in dilute acid (jlucagon is a 29 amino acid hormone known for its key role in the activation of adenylate cyclase (Rodbell, 1980) and the maintenance of fuel homeostasis and for its possible involve-ment in the pathogenesis of diabetes mellitus (Unger & Orci, 1981). Recently investigative interests have increasingly focused on the development of a wide variety of modified de-rivatives to probe the molecular mechanisms involved in glu-cagon action as well as to search for clinically useful antag-onists of the hormone (Bregman et al., 1980). The general conclusion that can be reached from these numerous studies is that virtually the whole molecule participates in the receptor recognition process, and essentially the entire sequence is re-quired for the full expression of hormonal activity (Epand et al., 1981). However, the lipophilic carboxyl-terminal region seems to serve no essential function in the mechanism of action and may be important only for the high receptor affinity of the hormone (Wright et al., 1978; Hruby et al., 1981). It has been suggested that receptor binding involves a helical con-former of glucagon induced or stabilized at the receptor by hydrophobic interactions involving residues in the carboxylterminal region of the molecule (Sasaki et al., 1975). The hydrophobic, helix-favoring methionine residueat position 27 has been considered to be particularly important for receptor binding since it appearsto facilitate helix formation in glu-cagon, and the ability of glucagon derivatives to assume an-helical conformation appears to correlate with their receptor