FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Can starch be a reagent in non-enzymatic glycosylation of proteins?


Non-enzymatic glycosylation of proteins plays an important role in the development of the diabetic complications and the aging processes. In nature, starch is the lipid-metallo-protein complex. The starchprotein complexes may serve as the source of the amino and aldehyde groups.This investigation was carried out to test the hypothesis that the starch can be a reagent in non enzymatic glycosylation of proteins in the physiological pH. Two suspensions were incubated: (1) Potato starch in the phosphate buffer at pH 6.0, 7.0 and 8.0, at 37°C for 24 h, (2) Potato starch in the phosphate buffer a leucine solution added. Amino nitrogen and glucose were determined. The decrease in the content of the amino groups during the incubation was observed for all starch suspensions. The highest decrease of the amino groups occurred at pH 6.0, and the lowest at pH 8.0. The addition of leucine to the starch suspensions intensified a decrease in amino group amount during the incubation. The content of aldehyde groups increased mostly during the incubation at pH 6.0 and decreased at the higher pH. The liberation of aldehyde groups from the starch suspension was not influenced by the addition of leucine. The increase the aldehyde group number during the incubation proves that starch was hydrolysed. However, the increase of amino points to the Maillard reactions which can include different components of the starch complex. Finally, the results seem to confirm our hypothesis, that starch can react on the non-enzymatic glycosylation of proteins at physiological pH.