Peptidomic analyses: The progress in enrichment and identification of endogenous peptides

Peptidomics is the comprehensive profiling of endogenous peptides from the biological sources. As with genome, transcriptome, proteome and metabolome, the peptidome is directly related with individuals' physiological state at the peptide level, which can be one of the most promising sources of pathophysiological information. Thus a comprehensive understanding of peptidome is very meaningful for clinical applications. However, low-abundance endogenous peptides present in highly complex biological environments with large heterogeneity in sizes and charges, making peptidome studies challenging. In order to clarify the peptidome in biological samples, numerous technologies and analytical methods in peptidomics have been developed which greatly promote the subject going forward. In this review, recent advances on technologies and methods developed for peptidome research are summarized with emphasis on the ingeniously designed adsorbents for peptide extract, MS technologies for peptide characterization, and data mining for function elucidation. Existing challenges and future perspectives in peptidomics are discussed.