title: Water-soluble peptides in Cheddar cheese: isolation and identification of peptides in the diafiltration retentate of the water-soluble fraction.
abstract: The water-soluble extract of Cheddar cheese was fractionated by diafiltration using 10 kDa cut-off membranes. Peptides were isolated from the diafiltrate retentate by chromatography on DEAE-cellulose with a linear NaCl gradient in 50 mM-Tris-HCl. pH 8.6, and reversed-phase HPLC or electroblotting from urea-PAGE gels. Peptides were identified by determining N-terminal amino acid sequences and mass spectrometry. Most (45) of the total 51 peptides identified in the diafiltrate retentate originated from beta-casein, especially from a short region in the N-terminal half of the molecule. Only six peptides originated from alpha s1-casein; beta-lactoglobulin was also identified in the retentate. The origin of most of these peptides could be explained on the basis of known specificities of lactococcal cell envelope proteinases.
authors.affiliation: Department of Food Chemistry, University College, Cork, Irish Republic.
authors.forename: T K
authors.initials: TK
authors.lastname: Singh
authors.forename: P F
authors.initials: PF
authors.lastname: Fox
authors.forename: A
authors.initials: A
authors.lastname: Healy
mesh_terms: D000595:Amino Acid Sequence; D002611:Cheese / Q000032:analysis*; D005591:Chemical Fractionation; D002848:Chromatography, DEAE-Cellulose; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005374:Filtration; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification*; D017421:Sequence Analysis; D012995:Solubility; D014867:Water
chemical_list: D010455:Peptides; D014867:Water