Mapping of peptides and protein fragments in human urine using liquid chromatography-mass spectrometry.

A method for the mapping of peptide mixtures, heterogeneous with respect to the concentration and the size of individual peptides, was established with the aim of obtaining a comprehensive analysis of human urine peptides. Peptide extraction and fractionation were optimized to achieve a two-step analysis, using reversed-phase and ion-exchange chromatography. Highly sensitive detection of peptides was performed by coupling microbore HPLC with electrospray mass spectrometry (ESI-MS). Peptides such as urodilatin, angiotensin and fragments of psoriasin, granulin and uromodulin were isolated and sequenced. The procedure presented here is a tool for the analysis of complex peptide mixtures from human urine.