title: Analysis of the urinary peptidome associated with Helicobacter pylori infection.
abstract: OBJECTIVE
  To investigate the relationship between urinary peptide changes and Helicobacter pylori (H. pylori) infection using urinary peptidome profiling.
  
  
  METHODS
  The study was performed in volunteers (n=137) who gave informed consent. Urinary peptides were enriched by magnetic beads based weak cation exchange chromatography and spectrums acquired by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). ClinProTools bioinformatics software was used for statistical analysis and the recognition of peptide patterns. The marker peptides were identified by LTQ Obitrap XL tandem MS.
  
  
  RESULTS
  Approximately 50 proteins or peptides which loaded onto the magnetic beads were detected by MALDI-TOF MS. By optimizing the parameters of the model, the Genetic Algorithm model had good recognition capability (97%) and positive predictive value (94%). Based on the model, 2 markers with molecular masses of 6788 and 1912 Da were found that differentiated between H. pylori positive and negative volunteers. The m/z 1912 sequence was parsed as SKQFTSSTSYNRGDSTF. The peptide was identified as isoform 1 of the fibrinogen α chain precursor, whose concentration in urine was markedly higher in H. pylori infected volunteers than in H. pylori non-infected ones.
  
  
  CONCLUSIONS
  The appearance of urinary fibrinogen degradation products is caused by an active H. pylori-induced process.
authors.affiliation: National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Di
authors.initials: D
authors.lastname: Xiao
authors.forename: Fan-Liang
authors.initials: FL
authors.lastname: Meng
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: He
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Gu
authors.forename: Jian-Zhong
authors.initials: JZ
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D015415:Biomarkers / Q000652:urine; D005260:Female; D016481:Helicobacter Infections / Q000652:urine*; D016480:Helicobacter pylori / Q000378:metabolism* / Q000472:pathogenicity; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification* / Q000652:urine*; D014551:Urinary Tract / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D010455:Peptides