Abstract
The interaction between proteins and sugars, termed as glycation has been a subject of increasing study over the past decade. The aim of the present study was to investigate the non-enzymatic interaction of thiol- proteinase inhibitor (cystatin) with three reducing sugars glucose, fructose and ribose. The behaviour of glycated cystatin was monitored by change in its hyperchromicity at 280nm, tryptophan fluorescence and Maillard fluorescence. The antipapain activity of glycated cystatin was found to be significantly lower than its non-glycated form. It was found that the incubation of cystatin with all the three sugars led to a parallel decrease in tryptophan fluorescence, enhancement in Maillard fluorescence and hyperchromicity in the UV-region. Among the three sugars studied ribose was found to be the most active in inducing structural and conformational alterations in the protein.