title: Relative quantification of tau-related peptides using guanidino-labeling derivatization (GLaD) with online-LC on a hybrid ion trap (IT) time-of-flight (ToF) mass spectrometer.
abstract: Development of a quantification method based on isotopic variants of O-methyl isourea (OMIU) in conjunction with reversed-phase (RP) liquid chromatography (LC) electrospray mass spectrometry is described for determining the relative quantification of tau-related peptides Ac-VQIVXK-NH2. Extracted ion chromatograms of the mass spectrometric data derived from online microcapillary LC separation identifies the retention times of the isotopically derivatized peptides together with their ion abundances. Data-dependent MSMS analysis of both derivatized variants of the same peptide provides a complementary method for identification and resolution between isobaric species. In addition, with respect to offline LC MALDI a larger number of analogues are detected and formation of amyloid is also observed for the aspartic acid and histidine-containing peptides.
authors.affiliation: Shimadzu Research Laboratory, Manchester, United Kingdom.
authors.forename: Jessica Z
authors.initials: JZ
authors.lastname: Bereszczak
authors.forename: Francesco L
authors.initials: FL
authors.lastname: Brancia
authors.forename: Federico A
authors.initials: FA
authors.lastname: Rojas Quijano
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Goux
mesh_terms: D000682:Amyloid / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D006146:Guanidines / Q000737:chemistry*; D008782:Methylurea Compounds / Q000737:chemistry; D009154:Mutation; D009842:Oligopeptides / Q000032:analysis* / Q000737:chemistry; D010449:Peptide Mapping; D020033:Protein Isoforms; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D016875:tau Proteins / Q000032:analysis* / Q000737:chemistry
chemical_list: D000682:Amyloid; D006146:Guanidines; D008782:Methylurea Compounds; D009842:Oligopeptides; D020033:Protein Isoforms; C510485:acetyl-valyl-glutaminyl-isoleucyl-valyl-tyrosyl-lysinamide; D016875:tau Proteins; C002249:O-methylisourea