Methylation of glucagon, characterization of the sulfonium derivative, and regeneration of the native covalent structure.
Methylation of glucagon, characterization of the sulfonium derivative, and regeneration of the native covalent structure.
复制标题
胰高血糖素的甲基化、锍衍生物的表征以及天然共价结构的再生。
DOI：
10.1021/bi00645a027
复制
发表时间：
1977
期刊：
影响因子：
2.9
通讯作者：
R. S. Gurd
中科院分区：
文献类型：
--
作者：
T. Rothgeb;B. Jones;D. Hayes;R. S. Gurd
胰高血糖素的单个甲硫氨酸残基的甲基化是在 pH 为 3.5 时在 8 M 尿素和碘甲烷中完成的。反应产物是可溶性锍衍生物，S-甲基胰高血糖素，可以以高度纯化的形式分离。通过氨基酸分析及其对大鼠肝质膜腺苷酸环化酶系统的影响来表征该衍生物。 S-甲基胰高血糖素确实会刺激腺苷酸环化酶系统；然而，其活性比天然激素观察到的活性低约 500 倍。该衍生物的溶解度足够大，可以对分子进行进一步修饰，然后在后续阶段进行去甲基化。 S-甲基胰高血糖素的去甲基化可再生原始共价结构，并通过在 pH 10.5 下用 Cleland 试剂处理来完成。再生激素的氨基酸组成及其刺激腺苷酸环化酶系统的能力与天然胰高血糖素没有区别。整个甲基化-去甲基化反应序列已完成，产率接近 75%。该技术适用于天然胰高血糖素的同位素富集，并且很可能适用于选定的其他含蛋氨酸的肽。
The methylation of the single methionine residue of glucagon is accomplished at a pH of 3.5 in 8 M urea with methyl iodide. The reaction product is a soluble sulfonium derivative, S-methylglucagon, which can be isolated in a highly purified form. This derivative is characterized by amino acid analysis and its effect on the adenylyl cyclase system of rat liver plasma membranes. S-Methylglucagon does stimulate the adenylyl cyclase system; however, its activity is approximately 500 times less than that observed with the native hormone. The solubility of this derivative is great enough to allow for further modifications of the molecule which can be followed at a later stage by demethylation. Demethylation of S-methylglucagon regenerates the original covalent structure and is accomplished by treatment with Cleland's reagents at a pH of 10.5. The regenerated hormone is indistinguishable from native glucagon by its amino acid composition and its ability to stimulate the adenylyl cyclase system. The entire methylation-demethylation reaction sequence has been carried out with yields that approach 75%. The technique is suitable for the isotopic enrichment of native glucagon and may well be applicable to selected other methionine-containing peptides.