Department of Biochemistry, Faculty of Medicine, A.M.U., Aligarh 202002, UP, India.
Arch Biochem Biophys. 2012 Jun 1;522(1):17-25. doi: 10.1016/j.abb.2012.04.005. Epub 2012 Apr 10.
Proteins modifications in diabetes may lead to early glycation products (EGPs) as well as advanced glycation end products (AGEs). Whereas no extensive studies have been carried out to assess the role of EGPs in secondary complications of diabetes, numerous investigators have demonstrated the role of AGEs. Early glycation involves attachment of glucose on ε-NH2 of lysine residues of proteins leading to generation of the Amadori product (an early glycation species). This study reports the structural and immunological characterization of EGPs of HSA because we believe that during persistent hyperglycemia the HSA, one of the major blood proteins, can undergo fast glycation. Glucose mediated generation of EGPs of HSA was quantitated as Amadori products by NBT assay and authenticated by boronate affinity chromatography and LC/MS. Compared to native HSA changes in glycated-HSA were characterized by hyperchromicity, loss in fluorescence intensity and a new peak in the FTIR profile. Immunogenicity of native- and glycated-HSA was evaluated by inducing antibodies in rabbits. Results suggest generation of neo-epitopes on glycated-HSA rendering it highly immunogenic compared to native HSA. Quantization of EGPs of HSA by authentic antibodies against HSA-EGPs can be used as marker for early detection of the initiation/progression of secondary complications of diabetes.
糖尿病中的蛋白质修饰可能导致早期糖基化产物 (EGPs) 以及晚期糖基化终产物 (AGEs)。虽然没有广泛的研究来评估 EGPs 在糖尿病的继发性并发症中的作用，但许多研究人员已经证明了 AGEs 的作用。早期糖基化涉及葡萄糖附着在蛋白质赖氨酸残基的 ε-NH2 上，导致 Amadori 产物（早期糖基化产物）的生成。这项研究报告了 HSA 的 EGPs 的结构和免疫学特征，因为我们相信在持续高血糖期间，HSA（主要血液蛋白之一）可能会经历快速糖基化。通过 NBT 测定法定量测定葡萄糖介导的 HSA 的 EGPs 的生成作为 Amadori 产物，并通过硼酸亲和色谱法和 LC/MS 进行验证。与天然 HSA 相比，糖基化-HSA 的变化特征为光密度增加、荧光强度降低和 FTIR 图谱中出现新峰。通过在兔子中诱导抗体来评估天然 HSA 和糖基化-HSA 的免疫原性。结果表明，糖基化-HSA 上产生了新的表位，使其比天然 HSA 具有更高的免疫原性。通过针对 HSA-EGPs 的特异性抗体定量 HSA 的 EGPs 可作为早期检测糖尿病继发性并发症的起始/进展的标志物。
