Khan Mohd Shahnawaz, Tabrez Shams, Rabbani Nayyar, Shah Aaliya
Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
King Fahd Medical Research Center, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
J Fluoresc. 2015 Nov;25(6):1721-6. doi: 10.1007/s10895-015-1658-2. Epub 2015 Sep 26.
The non-enzymatic reaction between reducing sugars and proteins has received increased attention in nutritional and medical research recently. In the current manuscript, effect of glycation in structural changes of human serum albumin (HSA) by the metabolites of glucose such as glyoxal, methylglyoxal and glyceraldehyde was studied using different spectroscopy techniques. Glycation of HSA was monitored by following advanced glycation end-products (AGEs) fluorescence changes, HSA intrinsic fluorescence measurement, extrinsic fluorescence using 8-analino 1-nephthlene sulfonic acid (ANS) dye, and circular dichroism (CD) studies. AGEs were formed within 7 days of incubation with glyoxal, methylglyoxal and glyceraldehyde. However, methylglyoxal induced significant structural changes in HSA compared with glyoxal and glyceraldehydes. Moreover, ANS binding to native and glycated-HSA showed difference in binding pattern of these metabolites to HSA. The CD spectrum revealed changes in the secondary structure of HSA upon glycation when compared to native HSA. Furthermore, the MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay established the cytotoxicity of the glycated- HSA towards human liver carcinoma (HepG2) cell lines via the production of reactive oxygen species.
还原糖与蛋白质之间的非酶促反应近来在营养和医学研究中受到了更多关注。在当前的手稿中，使用不同的光谱技术研究了乙二醛、甲基乙二醛和甘油醛等葡萄糖代谢产物对人血清白蛋白（HSA）结构变化的糖基化作用。通过跟踪晚期糖基化终产物（AGEs）荧光变化、HSA固有荧光测量、使用8-氨基-1-萘磺酸（ANS）染料的外在荧光以及圆二色性（CD）研究来监测HSA的糖基化。在与乙二醛、甲基乙二醛和甘油醛孵育7天内形成了AGEs。然而，与乙二醛和甘油醛相比，甲基乙二醛在HSA中诱导了显著的结构变化。此外，ANS与天然HSA和糖基化HSA的结合显示出这些代谢产物与HSA结合模式的差异。与天然HSA相比，CD光谱揭示了糖基化后HSA二级结构的变化。此外，MTT（3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐）试验通过活性氧的产生确定了糖基化HSA对人肝癌（HepG2）细胞系的细胞毒性。
