title: Identification of N-acetyl Proline-Glycine-Proline (acPGP) in human serum of adults and newborns by liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  N-acetyl Proline-Glycine-Proline (acPGP) is a novel neutrophil chemoattractant. However, no studies have been reported to identify the presence of acPGP in human serum. The purpose of our study was to establish a method for measuring acPGP, and to determine whether acPGP is present in human serum.
  
  
  METHODS
  Serum samples were obtained from 22 healthy adults and 26 term and preterm newborns. For the sensitive analysis of acPGP, we utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a multiple reaction monitoring (MRM) positive ion mode.
  
  
  RESULTS
  The major product ions of acPGP ([M+H](+) ion, m/z 312) appeared at 112 and 140. The MRM (transition: m/z 312/112) chromatogram in human serum showed a single peak with the same retention time as that of authentic acPGP. The calibration curve of authentic acPGP was linear, and our quantitative results indicated high precision. The mean serum acPGP levels in adults and newborns were 6.3 and 18.7 pg/ml, respectively. In newborns, lower birth weight infants had significantly higher serum acPGP levels.
  
  
  CONCLUSIONS
  We established a method for the quantification of serum acPGP using LC-MS/MS, and this paper provides the first evidence for the presence of acPGP in human serum of adults and newborns.
authors.affiliation: Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Shibata
authors.forename: Ichiro
authors.initials: I
authors.lastname: Morioka
authors.forename: Chitose
authors.initials: C
authors.lastname: Ashi
authors.forename: Shizu
authors.initials: S
authors.lastname: Nagasaki
authors.forename: Chisato
authors.initials: C
authors.lastname: Tode
authors.forename: Satoru
authors.initials: S
authors.lastname: Morikawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Miwa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Enomoto
authors.forename: Kayoko
authors.initials: K
authors.lastname: Saiki
authors.forename: Naoki
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Atsuko
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Masafumi
authors.initials: M
authors.lastname: Matsuo
mesh_terms: D000328:Adult; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D009842:Oligopeptides / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: C428643:N-acetyl-proline-glycine-proline; D009842:Oligopeptides