Asian Journal of Biomedical and Pharmaceutical Sciences

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Biochemical Studies of In Vitro Glycation of Human DNA

Glucose can covalently bind to DNA by non-enzymatic process often termed as glycation. Glycation of DNA is of special interest due to its possible influence on the functionality of DNA and overall effect on gene expression. Glycation of DNA leads to formation of advanced glycation end products (AGEs). These AGEs may accumulate with time, overwhelming the enzymatic defense against glycation leading to loss of viability and gradually to cellular aging. In our study, different concentrations of glucose were incubated with human DNA for varying time periods. The reaction product was characterized by UV spectroscopy, nitroblue tetrazolium (NBT) reduction assay, melting temperature and electrophoretic study. Oxidation induced by glycation of DNA was also analyzed by scavenging studies. It was found that ultraviolet (UV) spectroscopic analysis of Glycated DNA shows hypochromicity, indicates the formation of advance glycated end products. Amadori product content was found high in glycated samples. Thermal denaturation of glycated DNA shows increase in Tm value by 4 oC and change in banding pattern of native and glycated adduct on agarose gel electrophoresis. The quenching effect of glutathione (GSH) provides clue for generation of free radicals during glycation. The DNA modified with D-glucose may be one of the etiological pathogenic factors for diabetes mellitus.

Author(s): Adil Wani, Shaheena Mushtaq, Haseeb Ahsan, Rizwan Ahmad