New insight into the effects of different glycation treatments on the structure and IgG-binding capacity of α-lactalbumin

Abstract

Alpha-lactalbumin (α-LA) is one of the allergens in cow's milk. Glycation modifications can be used to modulate the allergenicity of α-LA and to clarify the effects of glycation of three reducing sugars (D-fructose, D-ribose, and D-xylose) on the structure and immunoglobulin G (IgG)-binding capacity of α-LA. In this study, the colorimetric and spectroscopic methods reflect the degree of glycation. The structural properties of the glycation products were characterised using spectroscopic and chromatographic methods. The IgG-binding capacity was determined by an indirect competitive enzyme-linked immunosorbent assay. The results showed a decrease in free amino groups content, an increase in molecular weight. The α-helix content was reduced, but the β-sheet and irregular coil content increased, resulting in a more loosened protein structure. All three reducing sugar glycation products had higher IgG-binding capacity, suggesting that glycation has the potential to enhance α-LA allergenicity. This study provides different perspectives on the allergenicity of cow's milk allergens modified by different sugar glycations.