Hochschule Fresenius, University of Applied Sciences, Limburger Straße 2, 65510, Idstein, Germany.
Department of Chemistry in Pharmaceutical Sciences, Faculty of Pharmacy, Complutense University of Madrid, Plaza de Ramón y Cajal s/n, 28040, Madrid, Spain.
Anal Bioanal Chem. 2019 Dec;411(30):7967-7979. doi: 10.1007/s00216-019-02186-2. Epub 2019 Nov 22.
Naturally occurring fructosamines are of high clinical significance due to their potential use in diabetes mellitus monitoring (quantification of fructosylated hemoglobin, HbA) or for the investigation of their reactivity in consecutive reactions and harmfulness towards the organism. Here we report the specific synthesis of the fructosylated dipeptide L-valyl-L-histidine (Fru-Val-His) and fructosylated L-valine (Fru-Val). Both are basic tools for the development and validation of enzymatic HbA assays. The two fructosamine derivatives were synthesized via a protected glucosone intermediate which was coupled to the primary amine of Val or Val-His, performing a reductive amination reaction. Overall yields starting from fructose were 36% and 34% for Fru-Val and Fru-Val-His, respectively. Both compounds were achieved in purities > 90%. A HILIC-ESI-MS/MS method was developed for routine analysis of the synthesized fructosamines, including starting materials and intermediates. The presented method provides a well-defined and efficient synthesis protocol with purification steps and characterization of the desired products. The functionality of the fructosylated dipeptide has been thoroughly tested in an enzymatic HbA assay, showing its concentration-dependent oxidative degradation by fructosyl-peptide oxidases (FPOX). Graphical abstract.
天然存在的果糖胺因其在糖尿病监测中的潜在用途（糖化血红蛋白的定量，即 HbA）而具有重要的临床意义，或因其在连续反应中的反应性及其对机体的危害性而被研究。在这里，我们报告了果糖基二肽 L-缬氨酸-L-组氨酸（Fru-Val-His）和果糖基 L-缬氨酸（Fru-Val）的特异性合成。这两种果糖胺衍生物都是开发和验证酶法 HbA 测定的基本工具。这两种果糖胺衍生物是通过保护的葡糖酮中间体合成的，该中间体与 Val 或 Val-His 的伯胺偶联，进行还原胺化反应。从果糖开始的总收率分别为 Fru-Val 和 Fru-Val-His 的 36%和 34%。这两种化合物的纯度均大于 90%。开发了一种用于合成果糖胺的亲水作用色谱-电喷雾串联质谱（HILIC-ESI-MS/MS）方法，包括起始材料和中间体。所提出的方法提供了一种定义明确且高效的合成方案，包括纯化步骤和所需产物的表征。该方法对合成的果糖基二肽进行了彻底的测试，在酶法 HbA 测定中显示其通过果糖基肽氧化酶（FPOX）的浓度依赖性氧化降解。
