Fructosylation of Human Serum Albumin - Implications in diabetes mellitus

Aim:To investigate the alterations in human serum albumin (HAS) due to glycation with varying fructose concentration. Methods:Human serum albumin (HSA)was glycated using fructose and characterized it using physicochemical studies. The changes and modifications as a result of glycation were studied in a concentration- and time-dependent manner. Results:Characterization of fructosylated HSA resulted in hyperchromicity of UV spectrum, increase in AGEformation, quenching of tryptophan fluorescenceandSDS-PAGE. Amadori products formed were estimated by nitroblue tetrazolium. Higher carbonyl content and decreased thiol content was found in fructose modified HSA. Diabetic sera showed increased levels of malondialdehydeand protein carbonyls indicating enhanced oxidative stress. The diabetic seraalso showed higher recognition and binding capability with respect to glycated HSA than to native HSA, reflecting greater specificity to glycated HSA. Conclusion:Modification of proteins due to glycation leads to formation of epitopes that are regarded as non-self and lead to antibody production. Structural modifications may also reflect as changes in receptor binding properties and alteration in functions.