title: 5-Amino-1-naphthol, a novel 1,5-naphthalene derivative matrix suitable for matrix-assisted laser desorption/ionization in-source decay of phosphorylated peptides.
abstract: BACKGROUND
  Although matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) is an important method for post-translational modification (PTM) analysis, the conventional matrices, 2,5-dihydroxybenzoic acid (2,5-DHB) and 1,5-diaminonaphthalene (1,5-DAN), are poor in terms of the fragment ion yields of the phosphorylated peptides. The use of 5-amino-1-naphthol (5,1-ANL) as a novel matrix for ISD of phosphorylated peptides in MALDI time-of-flight mass spectrometry (TOFMS) is described here.
  
  
  METHODS
  We have evaluated the ion yields of ISD fragments obtained from phosphorylated peptides using three 1,5-naphthalene derivatives as MALDI-ISD matrices, i.e., 5,1-ANL, 1,5-DAN and 1,5-dihydroxynaphthalene (1,5-DHN). The signal-to-noise ratio (S/N) of c'-series ions obtained from these matrices was used to estimate their suitability for MALDI-ISD of non-modified and phosphorylated peptides.
  
  
  RESULTS
  The order of the S/N values of the ISD fragments for non-modified and phosphorylated peptides were 1,5-DAN > 5,1-ANL > 1,5-DHN and 5,1-ANL > 1,5-DHN > 1,5-DAN, respectively.
  
  
  CONCLUSIONS
  The newly introduced matrix 5,1-ANL gave highest ion yields of ISD fragments from mono-, di-, and tetraphosphorylated peptides, while 1,5-DAN was poor in the ISD ion yields for phosphorylated peptides.
authors.affiliation: Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama, 236-0027, Japan.
authors.forename: Issey
authors.initials: I
authors.lastname: Osaka
authors.forename: Mami
authors.initials: M
authors.lastname: Sakai
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Takayama
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives / Q000737:chemistry; D005841:Gentisates / Q000737:chemistry; D009284:Naphthols / Q000737:chemistry*; D010748:Phosphopeptides / Q000032:analysis / Q000737:chemistry*; D059629:Signal-To-Noise Ratio; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D005841:Gentisates; D009284:Naphthols; D010748:Phosphopeptides; C510889:1,5-diaminonaphthalene; C040607:5-amino-1-naphthol; D015081:2-Naphthylamine; C010925:2,5-dihydroxybenzoic acid