title: Peptidomic profile of milk of Holstein cows at peak lactation.
abstract: Bovine milk is known to contain naturally occurring peptides, but relatively few of their sequences have been determined. Human milk contains hundreds of endogenous peptides, and the ensemble has been documented for antimicrobial actions. Naturally occurring peptides from bovine milk were sequenced and compared with human milk peptides. Bovine milk samples from six cows in second-stage peak lactation at 78-121 days postpartum revealed 159 peptides. Most peptides (73%) were found in all six cows sampled, demonstrating the similarity of the intramammary peptide degradation across these cows. One peptide sequence, ALPIIQKLEPQIA from bovine perilipin 2, was identical to another found in human milk. Most peptides derived from β-casein, αs1-casein, and αs2-casein. No peptides derived from abundant bovine milk proteins such as lactoferrin, β-lactoglobulin, and secretory immunoglobulin A. The enzymatic cleavage analysis revealed that milk proteins were degraded by plasmin, cathepsins B and D, and elastase in all samples.
authors.affiliation: Department of Food Science and Technology, ‡Foods for Health Institute, and #Department of Chemistry, University of California-Davis , One Shields Avenue, Davis, California 95616, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Dallas
authors.forename: Andres
authors.initials: A
authors.lastname: Guerrero
authors.forename: Evan A
authors.initials: EA
authors.lastname: Parker
authors.forename: Luis A
authors.initials: LA
authors.lastname: Garay
authors.forename: Aashish
authors.initials: A
authors.lastname: Bhandari
authors.forename: Carlito B
authors.initials: CB
authors.lastname: Lebrilla
authors.forename: Daniela
authors.initials: D
authors.lastname: Barile
authors.forename: J Bruce
authors.initials: JB
authors.lastname: German
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D006801:Humans; D007774:Lactation; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D008895:Milk, Human / Q000737:chemistry; D010449:Peptide Mapping; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010455:Peptides
keywords: bioactive peptides; bovine milk; peptidomics; protease