Sheep’s Milk: a deep exploration of the low-abundance proteome

Sheep’s Milk: a deep exploration of the low-abundance proteome Antonella Di Francesco a), Vincenzo Cunsolo a), Elisa Fasoli b), Vera Muccilli a), Maria Nicoletti b), Serafina Gallina a), Rosaria Saletti a), Pier G. Righetti b), Salvatore Foti a)a) Department of Chemical Sciences, University of Catania, Catania, Italyb) Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Milano, ItalyIn the last few years many types of mammalian milk has been subjected to extensive proteomic investigations, due to the importance of this biological fluid in nutrition and also for identifying sources of hypoallergenic alternatives to bovine milk [ ]. On this respect, many clinical trials have reported real benefits from using non-bovine milks as an alternative in cases of cow’s milk allergy, even if allergies to non-bovine milk proteins have also been documented. Sheep’s milk (SM), as well as goat’s, have been widely used for feeding babies, but their use as a possible alternative to cow’s milk (CM) for allergic subjects is still debated [ ]. Indeed, it has been shown that many children who are allergic to CM are also sensitized to proteins of SM, probably reflecting the close phylogenetic relations between these animals and the high sequence identity of their homologue proteins. Milk allergy is mainly due to the most abundant proteins, but different studies have highlighted that also minor proteins are involved in this pathology. As a consequence, a knowledge of milk protein fractions, including minor components, became a priority for many researchers. So far, exploration of the less abundant proteins only regards bovine, swine, goat and donkey milks [ , ]. The present work reports some preliminary results about a deep characterization of SM proteome by coupling the power of the Combinatorial Peptide Ligand Library (CPLL) technology with SDS-PAGE, high resolution nLC-nESI MS/MS and database searching using both the MASCOT engine and PEAKS de novo sequencing.Corresponding Author:Antonella Di FrancescoPhDDepartment of Chemical Sciences, University of Catania, Viale A. Doria, 6 - Catania, Italyantonella.difrancesco@alice.it +39 0957385041References[ ] Yang Y, Bu D, Zhao X, Sun P, Wang J, Zhou L. Proteomic analysis of cow, yak, buffalo, goat and camel milk whey proteins: quantitative differential expression patterns. J Proteome Res 2013;12:1660-7.[ ] Ah-Leung S, Bernard H, Bidat E, Paty E, Rancé F, Scheinmann P, Wal JM. Allergy to goat and sheep milk without allergy to cow's milk. Allergy 2006;61:1358-65.[ ] Cunsolo V, Muccilli V, Fasoli E, Saletti R, Righetti PG, Foti S. Poppea's bath liquor: the secret proteome of she-donkey's milk. J Proteomics 2011;74:2083-99.[ ] Cunsolo V, Fasoli E, Saletti R, Muccilli V, Gallina S, Righetti PG, Foti S. Zeus, Aesculapius, Amalthea and the proteome of goat milk. J. Proteomics 2015; 128: 69-82