A Biophysical Comparison of Human Serum Albumin to be Glycated In Vivo and In Vitro

The glycation process includes the arrangement of proteins with chemically reversible early glycation products, Schiff bases and Amadori adducts. These early products endure slow and complex rearrangements to create advanced glycation end-products (AGEs) that are involved in diabetic complications. Here, the biophysical characteristics of in vitro glycated human serum albumin (HSA) are compared to those of HSA glycated in vivo. The changes in the content of α-helices, AGE-specific fluorescence intensity, extent of lysine residue modification, and surface tension value and also the formation of Amadori products in HSA are similar in both conditions. It was observed, however, that arginine residues were modified only under physiological conditions (in vivo), while the same did not occur in vitro. This difference was related to the presence of 3-deoxyglucosone, a 1,2-dicarbonyl compound derived from glucose under physiological conditions. Therefore, the biophysical studies on the HSA glycation process in vitro are credible.