Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10532676 | Analytical Biochemistry | 2011 | 13 Pages |
Abstract
The simplest model-that authentic tandem mass spectrometry (MS/MS) spectra are no different from noise, random spectra, or false-positive results-may be directly examined by chi-square comparison of the peptide-to-protein distribution. The peptide-to-protein distribution of a set of 4151 redundant blood proteins identified by X!TANDEM indicated that there is a low probability that the authentic data were the same as noise, random spectra, or false-positive correlations (PÂ <Â 0.0001). In contrast, a competition for significance failed to distinguish approximately 90% of authentic blood proteins from those of noise, random spectra, or false-positive results (PÂ <Â 0.01) and apparently incurred a large type II error (false negative). The chi-square test of peptide-to-protein frequency distributions was found to be an efficient means to distinguish authentic data from false-positive results. Frequency-based statistics unambiguously demonstrated that proteins can be identified by liquid chromatography-electrospray ionization-MS/MS from human blood with acceptable confidence. Thus, the chi-square fit of the peptide-to-protein distribution could distinguish authentic data from random or false-positive data, but the score distribution method could not separate real results from false results.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Peihong Zhu, Peter Bowden, Monika Tucholska, Du Zhang, John G. Marshall,