Lu G S, Mojsov S, Merrifield R B
Int J Pept Protein Res. 1987 Apr;29(4):545-57.
[Tyr22] glucagon and [desHis1, Tyr22] glucagon were synthesized by an improved solid phase procedure on a Pam-resin. The course of the synthesis was monitored by quantitative ninhydrin analysis and preview sequencing. Following cleavage by the low/high HF method the peptides were purified by ion exchange chromatography and reverse phase HPLC. The overall yield of homogeneous isolated peptide from the first amino acid was 41%. Circular dichroism measurements on dilute solutions in mixed aqueous organic solvents at pH 2, 6.9 and 9.2 showed increased beta-sheet structure relative to glucagon. [Tyr22] glucagon was a full agonist with 20-30% activity in the rabbit blood glucose assay and 10% activity in the rat liver membrane adenyl cyclase assay. [desHis1, Tyr22] glucagon had only a trace of activity in the adenyl cyclase assay (less than 0.002%) but bound to membranes in a competitive [125I] glucagon assay 1.0% as well as glucagon. The analog completely inhibited formation of cAMP by natural glucagon, with 50% inhibition at a ratio of 83:1 and pA2 = 6.7. The data are discussed in terms of models of glucagon structure in dilute solution.
[酪氨酸22]胰高血糖素和[去组氨酸1，酪氨酸22]胰高血糖素通过改进的固相方法在对氨基甲基苯甲酰胺树脂上合成。合成过程通过茚三酮定量分析和预测序进行监测。采用低/高氢氟酸法切割后，肽段通过离子交换色谱和反相高效液相色谱进行纯化。从第一个氨基酸开始，均一分离肽的总产率为41%。在pH值为2、6.9和9.2的混合水性有机溶剂稀溶液中进行的圆二色性测量显示，相对于胰高血糖素，β-折叠结构有所增加。[酪氨酸22]胰高血糖素在兔血糖测定中是一种完全激动剂，活性为20 - 30%，在大鼠肝膜腺苷酸环化酶测定中活性为10%。[去组氨酸1，酪氨酸22]胰高血糖素在腺苷酸环化酶测定中只有微量活性（小于0.002%），但在竞争性[125I]胰高血糖素测定中与膜结合的能力为胰高血糖素的1.0%。该类似物完全抑制天然胰高血糖素诱导的环磷酸腺苷（cAMP）形成，在83:1的比例下50%抑制，pA2 = 6.7。根据稀溶液中胰高血糖素结构模型对数据进行了讨论。
