Detergency effects of nanofibrillar amyloid formation on glycation of human serum albumin

The prolonged glycation of human serum albumin (HSA) results in significant changes in its structure. The identity of these structural changes and the influence of carbohydrates on these changes require further study. Here, we evaluated structural changes and amyloid formation of HSA upon incubation with Glc, Fru, or Rib. Fluorescence spectrophotometry, surface tension analysis, and transmission electron microscopy (TEM) were utilized to evaluate the structures of glycated HSA. The physicochemical properties including excess free energy, protein adsorption at the air-water interface, critical aggregation concentration (CAC), and surface activity indicated an increase in hydrophobicity and partial unfolding of HSA structure upon glycation. Thus, it appears that AGE products can act as detergents. Incubation of HSA with these sugars after 20 wks induced significant amyloid nanofibril formation. Together these results indicate that prolonged glycation of HSA is associated with a transition from helical structure to beta-sheet (amyloid formation).