In-Depth Characterization of Sheep (Ovis aries) Milk Whey Proteome and Comparison with Cow (Bos taurus)

PLoS One. 2015 Oct 8;10(10):e0139774. doi: 10.1371/journal.pone.0139774. eCollection 2015.

Abstract

An in-depth proteomic study of sheep milk whey is reported and compared to the data available in the literature for the cow whey proteome. A combinatorial peptide ligand library kit (ProteoMiner) was used to normalize protein abundance in the sheep whey proteome followed by an in-gel digest of a 1D-PAGE display and an in-solution digestion followed by OFFGEL isoelectric focusing fractionation. The peptide fractions obtained were then analyzed by LC-MS/MS. This enabled identification of 669 proteins in sheep whey that, to our knowledge, is the largest inventory of sheep whey proteins identified to date. A comprehensive list of cow whey proteins currently available in the literature (783 proteins from unique genes) was assembled and compared to the sheep whey proteome data obtained in this study (606 proteins from unique genes). This comparison revealed that while the 233 proteins shared by the two species were significantly enriched for immune and inflammatory responses in gene ontology analysis, proteins only found in sheep whey in this study were identified that take part in both cellular development and immune responses, whereas proteins only found in cow whey in this study were identified to be associated with metabolism and cellular growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Chromatography, High Pressure Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Isoelectric Focusing
  • Milk / metabolism*
  • Peptides / analysis
  • Proteome / isolation & purification
  • Proteome / metabolism*
  • Proteomics
  • Sheep
  • Sheep, Domestic
  • Tandem Mass Spectrometry
  • Trypsin / metabolism
  • Whey Proteins / metabolism*

Substances

  • Peptides
  • Proteome
  • Whey Proteins
  • Trypsin

Grants and funding

This project was funded by a Dean's Bequest Grant-in-Aid from the Otago School of Medical Sciences, University of Otago to AC. MH acknowledges receipt of the 2012 University of Otago Special Health Research Scholarship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.