用气相色谱法测定蛋白质中的蛋氨酸
The determination of methionine in proteins by gas-liquid chromatography.
作者信息
Ellinger G M, Duncan A
出版信息
Biochem J. 1976 Jun 1;155(3):615-21. doi: 10.1042/bj1550615.
Intact methionine residues in proteins were rapidly and precisely determined by measuring methyl thiocyanate released during the reaction with CNBr and separated by g.l.c. Conditions for the reaction and for chromatography on columns of Porapak P-S are described. The recovery of methyl thiocyanate from several methionine derivatives and analogues were examined. Carbamoylmethionine was adopted as a stable primary standard and ethyl thiocyanate as internal standard. The measured methionine content of several isolated proteins was close to the theoretical value indicated by previous work and the results for these and a range of food proteins agreed well with results obtained by ion-exchange chromatography after performic acid oxidation. Since CNBr does not react with methionine sulphoxide and a preliminary hydrolysis is not required, the method discriminates between methionine and any methionine sulphoxide that may be present. It could be useful in studies on the nutritional availability of methionine in processed foods.
通过测量与溴化氰反应过程中释放出的硫氰酸甲酯并利用气相色谱法进行分离，能够快速且精确地测定蛋白质中完整的甲硫氨酸残基。文中描述了该反应条件以及在Porapak P-S柱上进行色谱分析的条件。研究了从几种甲硫氨酸衍生物和类似物中回收硫氰酸甲酯的情况。采用氨甲酰甲硫氨酸作为稳定的一级标准品，硫氰酸乙酯作为内标。几种分离得到的蛋白质的甲硫氨酸实测含量接近先前研究表明的理论值，这些蛋白质以及一系列食品蛋白质的检测结果与过甲酸氧化后离子交换色谱法得到的结果高度一致。由于溴化氰不与甲硫氨酸亚砜反应且无需进行初步水解，该方法能够区分甲硫氨酸和可能存在的任何甲硫氨酸亚砜。它在研究加工食品中甲硫氨酸的营养可利用性方面可能具有实用价值。
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