We aim to explore and identify the high abundance of peptides in urine.Methods.
Random urine samples from 30 healthy individuals were purified by weak cationic-exchange magnetic beads (MB-WCX) and then analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Then the generated mass spectra of peptides were handled by ClinPro-Tools2.1 bioinformatics software and the high abundance of urinary peptide was filtered. Subsequently, the amino acid sequences of highly expressed peptides were identified by a nano-liquid chromatography-tandem mass spectrometry and the corresponding protein names were found by Sequest search.Results.
There were 159 urinary peptides of which mass to charge ratios (m/z) varied between 1,000 and 10,000 in the 30 healthy samples. Only peaks with average intensity >600 and the frequency >50% in the whole group were filtered. There were 15 peptides passed though the threshold and they were identified as fragments of fibrinogen alpha chain precursor, vitronectin precursor, inter-alpha-trypsin inhibitor heavy chain H4, complement component 3, prothrombin, apolipoprotein C-II, and alpha-fetoprotein.Conclusion.
These urinary peptides could be used for further research on urine.