Proteomic analysis provides new insight into the chicken eggshell cuticle

J Proteomics. 2012 May 17;75(9):2697-706. doi: 10.1016/j.jprot.2012.03.019.

Abstract

The cuticle is the outermost layer of the avian eggshell, whose protein constituents remain virtually unknown. We hypothesize that cuticle components play a major role in microbial resistance, since eggs with incomplete or absent cuticle are more susceptible to bacterial contamination. In this study we extracted proteins from the outermost non-calcified layer of the cuticle of chicken eggs and subjected them to LC/MS/MS proteomic analysis. We identified 47 cuticle proteins with high confidence and reproducibility. Two proteins, similar to Kunitz-like protease inhibitor and ovocalyxin-32 (a carboxypeptidase A inhibitor), were the most abundant of the cuticle proteins. A number of proteins known to have antimicrobial activity in the egg were detected (lysozyme C, ovotransferrin, ovocalyxin-32, cystatin, ovoinhibitor) as well as possible new candidates (myeloperoxidase, ovocalyxin-36 and members of the SERPIN family). This is the first comprehensive report of cuticle proteome, a starting point to determine cuticle function and the molecular basis of its antimicrobial properties.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chickens
  • Chromatography, Liquid
  • Egg Proteins / analysis*
  • Egg Proteins / isolation & purification
  • Egg Shell / chemistry*
  • Protease Inhibitors / isolation & purification
  • Proteome / analysis
  • Proteomics*
  • Tandem Mass Spectrometry

Substances

  • Egg Proteins
  • Protease Inhibitors
  • Proteome
  • ovocalyxin 32