Peptidomics profiling reveals the functions of endogenous peptides and parent proteins in donkey colostrum and mature milk

Abstract

The endogenous peptides in milk are produced by protease hydrolysis in the mammary gland. They are important nutritional components with various biological activities. This study used 4D-label-free peptidomics technology to identify 5343 endogenous peptides from 933 parent proteins in donkey colostrum (DC) and 3726 endogenous peptides from 650 parent proteins in donkey mature milk (DM) by DB search. Furthermore, we screened non-toxic, non-allergenic bioactive peptides. Gene Ontology (GO) analysis revealed the biological processes, molecular functions, and cellular components of these parent proteins. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the predominant pathway of the differentially expressed parent proteins was associated with the ribosome. These findings provide significant insights into the functional diversity of parent proteins and the bioactivities of endogenous peptides in donkey milk during lactation. These results also offer theoretical guidance for the future development of donkey milk products.