Medical College of Wisconsin
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Simultaneous quantification and identification using 18O labeling with an ion trap mass spectrometer and the analysis software application "ZoomQuant". J Am Soc Mass Spectrom 2005 Jun;16(6):916-25 PMID: 15907706 PMCID: PMC2771642


Stable isotope labeling with (18)O is a promising technique for obtaining both qualitative and quantitative information from a single differential protein expression experiment. The small 4 Da mass shift produced by incorporation of two molecules of (18)O, and the lack of available methods for automated quantification of large data sets has limited the use of this approach with electrospray ionization-ion trap (ESI-IT) mass spectrometers. In this paper, we describe a method of acquiring ESI-IT mass spectrometric data that provides accurate calculation of relative ratios of peptides that have been differentially labeled using(18)O. The method utilizes zoom scans to provide high resolution data. This allows for accurate calculation of (18)O/(16)O ratios for peptides even when as much as 50% of a (18)O labeled peptide is present as the singly labeled species. The use of zoom scan data also provides sufficient resolution for calculating accurate ratios for peptides of +3 and lower charge states. Sequence coverage is comparable to that obtained with data acquisition modes that use only MS and MS/MS scans. We have employed a newly developed analysis software tool, ZoomQuant, which allows for the automated analysis of large data sets. We show that the combination of zoom scan data acquisition and analysis using ZoomQuant provides calculation of isotopic ratios accurate to approximately 21%. This compares well with data produced from (18)O labeling experiments using time of flight (TOF) and Fourier transform-ion cyclotron resonance (FT-ICR) MS instruments.

Author List

Hicks WA, Halligan BD, Slyper RY, Twigger SN, Greene AS, Olivier M


Andrew S. Greene PhD Interim Vice Chair, Chief, Professor in the Biomedical Engineering department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Isotope Labeling
Mass Spectrometry
Molecular Sequence Data
Oxygen Isotopes
Protein Tyrosine Phosphatase, Non-Receptor Type 1
Protein Tyrosine Phosphatases
Reproducibility of Results
Vascular Endothelial Growth Factor A

View this publication's entry at the Pubmed website PMID: 15907706
jenkins-FCD Prod-169 3190624ff63883a964b0308a7647b09582875180