Table of Contents
International Journal of Proteomics
Volume 2011, Article ID 928391, 14 pages
Research Article

A Bayesian Model Averaging Approach to the Quantification of Overlapping Peptides in an MALDI-TOF Mass Spectrum

1Department of Electrical Engineering, ESAT/SCD Katholieke Universiteit Leuven, Kasteelpark Arenberg 10, Bus 2446, 3001 Heverlee, Belgium
2Wolfson Research Institute, Durham University, Queen's Campus University Boulevard, Thornaby, Stockton-on-Tees TS17 6BH, UK
3Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium
4I-BIOSTAT, Hasselt University, Agoralaan, Building D, 3590 Diepenbeek, Belgium

Received 9 November 2010; Revised 28 January 2011; Accepted 12 March 2011

Academic Editor: Xinning Jiang

Copyright © 2011 Qi Zhu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In a high-resolution MALDI-TOF mass spectrum, a peptide produces multiple peaks, corresponding to the isotopic variants of the molecules. An overlap occurs when two peptides appear in the vicinity of the mass coordinate, resulting in the difficulty of quantifying the relative abundance and the exact masses of these peptides. To address the problem, two factors need to be considered: (1) the variability pertaining to the abundances of the isotopic variants (2) extra information content needed to supplement the information contained in data. We propose a Bayesian model for the incorporation of prior information. Such information exists, for example, for the distribution of the masses of peptides and the abundances of the isotopic variants. The model we develop allows for the correct estimation of the parameters of interest. The validity of the modeling approach is verified by a real-life case study from a controlled mass spectrometry experiment and by a simulation study.