University of Wrocław, 50383 Wrocław, Poland.
Anal Biochem. 2011 Dec 15;419(2):81-7. doi: 10.1016/j.ab.2011.08.040. Epub 2011 Aug 27.
A nonenzymatic reaction of reducing sugars with the free amino group located at the N terminus of the polypeptide chain or in the lysine side chain results in glycation of proteins. The fragments of glycated proteins obtained by enzymatic hydrolysis could be considered as the biomarkers of both the aging process and diabetes mellitus. Here we propose a new method for the identification of peptide-derived Amadori products in the enzymatic digest of glycated proteins. The products of enzymatic hydrolysis of the model protein ubiquitin were incubated with H(2)(18)O under microwave activation. We observed that at these conditions the Amadori compounds selectively exchange one oxygen atom in the hexose moiety. The characteristic isotopic pattern of Amadori products treated with H(2)(18)O allows fast and convenient identification of this group of compounds, whereas nonglycated peptides are not susceptible to isotopic exchange.
非酶反应的还原糖与游离氨基基团位于多肽链的 N 端或赖氨酸侧链导致蛋白质的糖化。通过酶水解获得的糖化蛋白片段可被视为衰老过程和糖尿病的生物标志物。在这里，我们提出了一种用于鉴定糖化蛋白酶解产物中肽衍生的阿马多里产物的新方法。模型蛋白泛素的酶解产物与 H(2)(18)O 在微波激活下孵育。我们观察到，在这些条件下，阿马多里化合物选择性地在己糖部分交换一个氧原子。用 H(2)(18)O 处理的阿马多里产物的特征同位素模式允许快速方便地鉴定这一组化合物，而未糖化的肽不易发生同位素交换。
