CONFORMATION OF BETA-LACTOGLOBULIN AT AN OIL WATER INTERFACE AS DETERMINED FROM PROTEOLYSIS AND SPECTROSCOPIC METHODS/

The rates of appearance of tryptic peptides following the hydrolysis o f beta-lactoglobulin in solution or adsorbed at the oil/water interfac e of an emulsion were investigated as a function of time. It was also shown using hydrophobic labeling that the region 15-40 of beta-lactogl obulin was in the oil phase. The fluorescence results suggested that t he conformation of beta-lactoglobulin was modified upon adsorption at the oil/water interface and that at least one tryptophan in adsorbed b eta-lactoglobulin was in a more hydrophobic environment. The data obta ined by circular dichroism in the peptidic region indicated that the a dsorbed beta-lactoglobulin was characterized by a higher content in al pha-helix than the protein in solution. (C) 1998 Academic Press.