Polyphemus, Odysseus and the ovine milk proteome

In the last years the amount of ovine milk production, mainly used to formulate a wide range of different and exclusive dairy products often categorized as gourmet food, has been progressively increasing. Taking also into account that sheep milk (SM) also appears to be potentially less allergenic than cow's one, an in-depth information about its protein composition is essential to improve the comprehension of its potential benefits for human consumption. The present work reports the results of an in-depth characterization of SM whey proteome, carried out by coupling the CPLL technology with SDS-PAGE and high resolution UPLC-nESI MS/MS analysis. This approach allowed the identification of 718 different protein components, 644 of which are from unique genes. Particularly, this identification has expanded literature data about sheep whey proteome by 193 novel proteins previously undetected, many of which are involved in the defence/immunity mechanisms or in the nutrient delivery system. A comparative analysis of SM proteome known to date with cow's milk proteome, evidenced that while about 29% of SM proteins are also present in CM, 71% of the identified components appear to be unique of SM proteome and include a heterogeneous group of components which seem to have health-promoting benefits. The data have been deposited to the ProteomeXchange with identifier < PXD004556 >.