Condensation of glycosidic and aromatic structures on amino groups of β-lactoglobulin B <i>via </i>reductive alkylation. Solubility and emulsifying properties of the protein derivatives

Abstract

Nueleophilie primary amino groups of bovine ~-Iaetoglobulin B were modified with different aldehydes by an addition-elimination reaction eommonlynamed ."reductive alkylation". Subsequently resulting imines (Sehiff bases) were redueed, produeing secondary amines derivatives of this protein. Two kinds of ligands, differing by their hydrophobieity, were coupled to this protein: 81% and 69% of ~-Iaetoglobulin amino groups were modified with glucose and maltose, respectively; 31% and 44% of ~-Iaetoglobulin amino groups were modified with vanillin and benzaldehyde, respectively. Reversed-phase HPLC and eleetrophoresis of modified ~-Iactoglobulin indicated that, in the case of glycosylation, the condensation was rather homogeneous, while the modification with aromatie substituents was quite heterogeneous.