Poppea's bath liquor: the secret proteome of she-donkey's milk

Donkey's milk is today categorized among the best mother's milk substitute for allergic newborns, due to its much reduced or absent allergenicity, coupled to excellent palatability and nutritional value. However, up to the present, only a handful of proteins had been characterized, just about the standard eight to ten major ones known in all types of milk. By exploiting the combinatorial peptide ligand library technology, and treating large volumes (up to 300 mL) of defatted, de-caseinized (whey) milk, we have been able to identify 106 unique gene products, by far the largest description so far of this precious nutrient. Due to poor knowledge of the donkey's genetic asset, only 10% of the proteins could be identified by consulting the data base of Equus asinus; the largest proportion (70%) could be identified by homology with the proteins of Equus caballus.