title: QuantiSpec--Quantitative mass spectrometry data analysis of (15)N-metabolically labeled proteins.
abstract: For relative protein quantitation by mass spectrometry we metabolically labeled E. coli bacteria with (15)N-enriched diets. Proteins extracted from (15)N-labeled and unlabeled E. coli bacteria were mixed, separated by two-dimensional gel electrophoresis and enzymatically digested. The resulting tryptic peptides were analyzed by MALDI mass spectrometry. For the relative protein quantitation we developed fully automated software, QuantiSpec (Quantitative Mass Spectrometry Analysis Software), which uses data from MALDI TOF mass spectrometry and the Mascot database search engine. QuantiSpec detects natural as well as partially or fully labeled peptide isotope distributions. For each identified peptide the (15)N incorporation rate is determined by comparing the experimental to a set of theoretical isotope patterns based on the peptide sequence. Relative quantitation is accomplished by calculating the signal intensity ratios for each (14)N/(15)N peptide pair.
authors.affiliation: Max Planck Institute of Psychiatry, Proteomics and Biomarkers, Munich, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Haegler
authors.forename: Nikola S
authors.initials: NS
authors.lastname: Mueller
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Maccarrone
authors.forename: Eva
authors.initials: E
authors.lastname: Hunyadi-Gulyas
authors.forename: Christian
authors.initials: C
authors.lastname: Webhofer
authors.forename: Michaela D
authors.initials: MD
authors.lastname: Filiou
authors.forename: Yaoyang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Christoph W
authors.initials: CW
authors.lastname: Turck
mesh_terms: D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000737:chemistry*; D020543:Proteome / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
chemical_list: D029968:Escherichia coli Proteins; D009587:Nitrogen Isotopes; D020543:Proteome