Media type: E-Article Title: Enhanced specificity of bacterial spore identification by oxidation and mass spectrometry Contributor: Demirev, Plamen A. imprint: Wiley, 2004 Published in: Rapid Communications in Mass Spectrometry Language: English DOI: 10.1002/rcm.1680 ISSN: 0951-4198; 1097-0231 Keywords: Organic Chemistry ; Spectroscopy ; Analytical Chemistry Origination: Footnote: Description: <jats:title>Abstract</jats:title><jats:p>Addition of an oxidizing agent (e.g., hydrogen peroxide) to intact spores selectively and completely oxidizes Met‐containing biomarker proteins by formation of Met sulfoxides. This reaction increases the masses of the biomarker proteins observed in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) of <jats:italic>Bacillus</jats:italic> spores by Δ<jats:italic>m</jats:italic> = (16 × <jats:italic>n</jats:italic>) Da, where <jats:italic>n</jats:italic> is the number of Met residues in the sequence of each individual protein. The procedure is very rapid, and can be performed <jats:italic>in situ</jats:italic> (i.e., on the MALDI target). It confirms the identity of individual biomarkers by comparing the number of Met amino acids from the experimentally determined mass shifts with predictions for <jats:italic>n</jats:italic> from the tentative amino acid sequence for each protein. In turn, accurate determination of <jats:italic>n</jats:italic> for several biomarkers allows rapid validation of the initial spore identification by MALDI‐MS. Copyright © 2004 John Wiley & Sons, Ltd.</jats:p>