National Glycoengineering Research Center, Shandong University, Jinan, Shandong 250100, China.
Molecules. 2012 Jul 25;17(8):8782-94. doi: 10.3390/molecules17088782.
Non-enzymatic glycosylation or glycation involves covalent attachment of reducing sugar residues to proteins without enzyme participation. Glycation of glucose to human serum albumin in vivo is related to diabetes and many other diseases. We present an approach using liquid chromatography coupled to an electrospray ionization source of a hybrid ion trap-time of flight (IT-TOF-MS/MS) tandem mass spectrometer to identify the glycation sites on serum albumin from both a healthy person and a diabetic patient. The MetID software, which is commonly used for screening metabolites, is adapted for peptide fingerprinting based on both m/z values and isotopic distribution profiles. A total of 21 glycation sites from the healthy person and 16 glycation sites from the diabetic patient were identified successfully. We also demonstrate the use of matrix assisted laser desorption ionization-time of flight mass spectrometry to estimate the incorporation ratio of glucose to albumin during glycation. Results from this study show that the glycation in healthy person is more complicated than previously thought. Further analysis of incorporation ratio distribution may be necessary to accurately reflect the change of serum albumin glycation in diabetic patients.
非酶糖化或糖基化涉及没有酶参与的还原糖残基与蛋白质的共价结合。葡萄糖与人血清白蛋白在体内的糖化与糖尿病和许多其他疾病有关。我们提出了一种使用液相色谱与混合离子阱-飞行时间（IT-TOF-MS/MS）串联质谱仪的电喷雾源相结合的方法，来鉴定来自健康人和糖尿病患者的血清白蛋白上的糖化位点。MetID 软件通常用于筛选代谢物，经过改编后可用于基于质荷比（m/z）值和同位素分布轮廓的肽指纹图谱分析。成功鉴定了来自健康人的 21 个糖化位点和来自糖尿病患者的 16 个糖化位点。我们还展示了使用基质辅助激光解吸电离-飞行时间质谱法来估计糖化过程中葡萄糖与白蛋白的结合比例。该研究结果表明，健康人的糖化比以前想象的更为复杂。可能需要进一步分析结合比例分布，以准确反映糖尿病患者血清白蛋白糖化的变化。
