title: Protein-peptide interactions in mixtures of whey peptides and whey proteins.
abstract: The effects of several conditions on the amounts and compositions of aggregates formed in mixtures of whey protein hydrolysate, made with Bacillus licheniformis protease, and whey protein isolate were investigated using response surface methodology. Next, the peptides present in the aggregates were separated from the intact protein and identified with liquid chromatography-mass spectrometry. Increasing both temperature and ionic strength increased the amounts of both intact protein and peptides in the aggregates. There was an optimal amount of added intact WPI that could aggregate with peptides, yielding a maximal amount of aggregated material in which the peptide/protein molar ratio was around 6. Under all conditions applied, the same peptides were observed in the protein-peptide aggregates formed. The dominant peptides were beta-lg AB [f1-45], beta-lg AB [f90-108], and alpha-la [f50-113]. It was hypothesized that peptides could form a kind of glue network that can include beta-lactoglobulin via hydrophobic interactions at the hydrophobic binding sites at the surface of the protein.
authors.affiliation: Laboratory of Food Chemistry/Center for Protein Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Creusot
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
mesh_terms: D001407:Bacillus / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D013058:Mass Spectrometry; D008894:Milk Proteins / Q000737:chemistry* / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000737:chemistry*; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D010455:Peptides; D000067816:Whey Proteins; D010447:Peptide Hydrolases