Dipeptidyl peptidase IV (DPIV/CD26) degradation of glucagon -: Characterization of glucagon degradation products and DPIV-resistant analogs
Dipeptidyl peptidase IV (DPIV/CD26) degradation of glucagon -: Characterization of glucagon degradation products and DPIV-resistant analogs
复制标题
DOI：
10.1074/jbc.275.6.3827
复制
发表时间：
2000-02-11
影响因子：
4.8
通讯作者：
McIntosh, CHS
中科院分区：
文献类型：
--
作者：
Hinke, SA;Pospisilik, JA;McIntosh, CHS
在过去的十年中，许多研究的目标是确定胰高血糖素的结构-活性关系。最近，我们已经发现胰高血糖素（1-29）被二肽基肽酶IV（DPIV）水解以产生胰高血糖素（3-29）和胰高血糖素（5-29）;在人血清中，[焦谷氨酰（pGlu）（3）]胰高血糖素（3 - 29）由胰高血糖素（3- 29）形成，并且这防止胰高血糖素被DPIV（H.联合Demuth，K.格伦德大学Heiser，J. Pospisilik，S. Hinke，T. Hoffmann，F.罗切，D. Schlenzig，M.韦尔曼角McIntosh和R.佩德森，手稿正在编写中）。在目前的研究中，这些肽的生物活性进行了检查，在体外。氨基末端截短的肽在环AMP刺激测定中均表现为部分激动剂，中国仓鼠卵巢K1细胞过表达人胰高血糖素受体（效力：胰高血糖素（1-29）> [pGlu（3）]胰高血糖素（3 - 29）>胰高血糖素（5-29）> [Glu（9）]胰高血糖素（2-29））。在竞争结合实验中，[pGlu（3）]胰高血糖素（3-29）和胰高血糖素（5-29）对受体的亲和力均比胰高血糖素（1-29）低5倍，而胰高血糖素（3-29）表现出低18倍的亲和力。在所测试的肽中，仅胰高血糖素（5-29）显示拮抗剂活性，并且这与经典胰高血糖素拮抗剂[Glu（9）]胰高血糖素（2-29）相比是弱的。因此，胰高血糖素的DPIV水解产生胰高血糖素受体的低亲和力激动剂。作为指示DPIV降解胰高血糖素的证据的推论（Demuth，ct at，准备中的手稿），合成DPIV抗性类似物。基质辅助激光解吸/电离-飞行时间质谱法用于评估DPIV抗性，并允许降解动力学分析。在产生的几种类似物中，只有[D-Ser（2）]和[Gly（2）]胰高血糖素保留了高亲和力结合和生物学效力，与体外天然胰高血糖素相似。[D-Ser（2）]胰高血糖素在生物测定中表现出增强的高血糖活性，而[Gly（2）]胰高血糖素对DPIV降解没有完全抗性。
Over the past decade, numerous studies have been targeted at defining structure-activity relationships of glucagon. Recently, we have found that glucagon(1-29) is hydrolyzed by dipeptidyl peptidase IV (DPIV) to produce glucagon(3-29) and glucagon(5-29); in human serum, [pyroglutamyl (pGlu)(3)]glucagon(3-29) is formed from glucagon(3-29) and this prevents further hydrolysis of glucagon by DPIV (H.-U. Demuth, K. Glund, U. Heiser, J. Pospisilik, S. Hinke, T. Hoffmann, F. Rosche, D. Schlenzig, M. Wermann, C. McIntosh, and R. Pederson, manuscript in preparation). In the current study, the biological activity of these peptides was examined in vitro. The amino-terminally truncated peptides all behaved as partial agonists in cyclic AMP stimulation assays, with Chinese hamster ovary K1 cells overexpressing the human glucagon receptor (potency: glucagon(1-29) > [pGlu(3)]glucagon(3-29) > glucagon(3-29) > glucagon(5-29) > [Glu(9)]glucagon(2-29)). In competition binding experiments, [pGlu(3)]glucagon(3-29) and glucagon(5-29) both demonstrated 5-fold lower affinity for the receptor than glucagon(1-29), whereas glucagon(3-29) exhibited 18-fold lower affinity. Of the peptides tested, only glucagon(5-29) showed antagonist activity, and this was weak compared with the classical glucagon antagonist, [Glu(9)]glucagon(2-29). Hence, DPIV hydrolysis of glucagon yields low affinity agonists of the glucagon receptor. As a corollary to evidence indicating that DPIV degrades glucagon (Demuth, ct at, manuscript in preparation), DPIV-resistant analogs were synthesized. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry was used to assess DPIV resistance, and it allowed kinetic analysis of degradation. Of several analogs generated, only [D-Ser(2)] and [Gly(2)]glucagon retained high affinity binding and biological potency, similar to native glucagon in vitro. [D-Ser(2)]Glucagon exhibited enhanced hyperglycemic activity in a bioassay, whereas [Gly(2)]glucagon was not completely resistant to DPIV degradation.