Title 



A modelbased method for the prediction of the isotopic distribution of peptides
 
Author 



 
Abstract 



The process of monoisotopic mass determination, i.e., nomination of the correct peak of an isotopically resolved group of peptide peaks as a monoisotopic peak, requires prior information about the isotopic distribution of the peptide. This points immediately to the difficulty of monoisotopic mass determination, whereas a single mass spectrum does not contain information about the atomic composition of a peptide and therefore the isotopic distribution of the peptide remains unknown. To solve this problem a technique is required, which is able to estimate the isotopic distribution given the information of a single mass spectrum. Senko et al. calculated the average isotopic distribution for any mass peptide via the multinomial expansion (Yergey 1983) [1], using a scaled version of the average amino acid Averagine (Senko et al. 1995) [2]. Another method, introduced by Breen et al., approximates the result of the multinomial expansion by a Poisson model (Breen et al. 2000) [3]. Although both methods perform well, they have their specific limitations. In this manuscript, we propose an alternative method for the prediction of the isotopic distribution based on a model for consecutive ratios of peaks from the isotopic distribution, similar in spirit to the approach introduced by Gay et al. (1999) [5]. The presented method is computationally simple and accurate in predicting the expected isotopic distribution. Further, we extend our method to estimate the isotopic distribution of sulphurcontaining peptides. This is important because the naturally occurring isotopes of sulphur have an impact on the isotopic distribution of a peptide.   
Language 



English
 
Source (journal) 



Journal of the American Society for Mass Spectrometry.  New York, N.Y.  
Publication 



New York, N.Y. : 2008
 
ISSN 



10440305
 
Volume/pages 



19:5(2008), p. 703712
 
ISI 



000255722200010
 
Full text (Publishers DOI) 


  
Full text (publishers version  intranet only) 


  
