title: Neutrophil-derived azurocidin cleaves insulin-like growth factor-binding protein-1, -2 and -4.
abstract: OBJECTIVE
  Azurocidin is an important inflammatory mediator and considered to be an inactive serine protease homologue. It has previously been reported that azurocidin is a possible IGFBP-1 specific protease; however, the protease-activity of azurocidin was not isolated in its active form. The aim of this study was to determine the effect of neutrophil-derived azurocidin on the six different IGFBPs, focusing especially on IGFBP-1.
  
  
  METHODS
  IGFBPs were incubated with azurocidin in phosphate-buffered saline for 2 h and proteolysis was studied by SDS-PAGE. Analysis of azurocidin was performed by MALDI-TOF peptide mass fingerprint and MALDI-TOF/TOF peptide sequencing.
  
  
  RESULTS
  The neutrophil-derived preparation of azurocidin cleaved IGFBP-1, IGFBP-2 and IGFBP-4. IGFBP-1 bound to IGF-I was also degraded whereas IGF-II was shown to have an inhibitory effect on proteolysis of IGFBP-1. The proteolytically active preparation of neutrophil-derived azurocidin was found to be glycosylated and determined to be 31 kDa by SDS-PAGE.
  
  
  CONCLUSIONS
  Our results indicate that the neutrophil-derived preparation of azurocidin contains a protease activity which cleaves IGFBP-1, IGFBP-2 and IGFBP-4. These findings are of interest since both IGFBP-1 and azurocidin increase during inflammation. The effect of azurocidin on IGFBP- and IGF-activity needs to be further investigated.
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden. Katrin.Brandt@ki.se
authors.forename: Katrin
authors.initials: K
authors.lastname: Brandt
authors.forename: Kerstin
authors.initials: K
authors.lastname: Lundell
authors.forename: Kerstin
authors.initials: K
authors.lastname: Brismar
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000378:metabolism*; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000378:metabolism*; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C062991:AZU1 protein, human; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018974:Insulin-Like Growth Factor Binding Protein 4; D010455:Peptides; D020033:Protein Isoforms