Modification of bovine beta-lactoglobulin by glycation in a powdered stateor in an aqueous solution: Immunochemical characterization

Bovine beta-LG was modified by glycation with lactose in a powdered state o r in an aqueous solution. An immunological characterization was performed u sing monoclonal antibodies with defined epitopes. The results showed that t he structural changes were confined to the AB loop region of the molecules when glycation was conducted in a restricted water environment and had litt le consequences on the association state of glycated beta-LG. The protein c onformation was much more extensively modified when glycation was performed in an aqueous solution at 60 degrees C, despite a lower glycation extent. These structural changes were located at the dimer interface (AB loop, GH l oop, beta-strand I, and alpha-helix). These results allowed us to establish a relationship between the conformational changes and the modification of the association state of the glycated protein (formation of disulfide bridg es between the free thiol groups of two monomers), previously described.