Poster Presenter

AGE Characterization: High Sugar Concentration Indicating Hyperglycaemic Condition Stabilizes Secondary Structure of Human Serum Albumin
K. Bala, N. K. Gohil, J. Gomes
India

Formation of advanced glycation end products (AGEs) results due to the interaction of proteins with reducing sugars, this interaction influences protein structure and its functional properties. Human serum albumin (HSA) is the most abundant serum protein. AGEs are known to be involved in the pathogenesis of several diseases via signaling through its receptor. Numerous studies have been carried out on protein and glucose interactions with very high concentrations, but studies involving physiological concentration are very few. The objective of this investigation was to determine the effects of non-enzymatic glycation by glucose and ribose on the secondary structure of human serum albumin (HSA) and to also demonstrate the in vitro formation of AGEs by these two sugars under different physiological conditions.

AGE characterization has been done using different parameters. The formation of AGEs was monitored by UV and fluorescence spectroscopy. The changes in the secondary structure of HSA were determined by circular dichroism (CD) and infrared spectrometry (FTIR), electro spray ionisation mass spectrometry (ESI-MS), SDS- PAGE, thermodynamic, thermo-gravimetric profiles of the native and glycated proteins.

In vitro formation of AGE–HSA was characterized by different detailed protocols. Fluorescence study revealed formation of new glycophore after incubation for 50 days, indicating that duration of incubation plays an important role in formation of AGEs. The biochemical and biophysical analysis of the glycated protein reveals that higher concentration of glucose (20mM, hyperglycaemic conditions) has a stabilising effect on the secondary structure of HSA, which may slow down its turnover in-vivo and thus may be a possible reason for complications in diabetes.