Proteomic analysis provides new insight into the chicken  eggshell cuticle.
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.
Department of Cellular and Molecular Medicine, University of Ottawa, Canada.
Megan
M
Rose-Martel
Jingwen
J
Du
Maxwell T
MT
Hincke
D000818:Animals; D002645:Chickens; D002853:Chromatography, Liquid; D004527:Egg Proteins / Q000032:analysis* / Q000302:isolation & purification; D004528:Egg Shell / Q000737:chemistry*; D011480:Protease Inhibitors / Q000302:isolation & purification; D020543:Proteome / Q000032:analysis; D040901:Proteomics; D053719:Tandem Mass Spectrometry
D004527:Egg Proteins; D011480:Protease Inhibitors; D020543:Proteome; C439069:ovocalyxin 32