Isolation and identification of further peptides in the diafiltration retentate of the water-soluble fraction of Cheddar cheese.
Several peptides were isolated from the diafiltration retentate, prepared using 10 kDa membranes, of the water-soluble extract from a commercial mature Cheddar cheese and identified by amino acid sequencing and mass spectrometry. Most of the peptides were from the N-terminal half of the beta-casein, but peptides from alpha s1- and alpha s2-caseins were also identified; the extract also contained alpha-lactalbumin. Identified peptides showed the important role played by lactococcal cell envelope proteinases in the degradation of primary proteolytic products from alpha s1- and beta-caseins, produced by chymosin and plasmin respectively. Plasmin seemed to be involved in the hydrolysation of alpha s2-casein. Several phosphopeptides were identified and the action of phosphatase on these peptides was evident.
Singh
T K
TK
Department of Food Chemistry, University College, Cork, Irish Republic.
Fox
P F
PF
Healy
A
A
D000595:Amino Acid Sequence; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D002611:Cheese / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D012085:Chymosin / Q000378:metabolism; D005341:Fibrinolysin / Q000378:metabolism; D005374:Filtration; D013058:Mass Spectrometry; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000302:isolation & purification*; D017421:Sequence Analysis; D012995:Solubility; D014867:Water
D002364:Caseins; D010446:Peptide Fragments; D010455:Peptides; D014867:Water; D005341:Fibrinolysin; D012085:Chymosin