`Notice: IonSource




Mass Spectrometry Educational Resource



De Novo Peptide Sequencing Tutorial


2nd De Novo Exercise

q-TOF Data



Here is an MS/MS q-TOF spectrum for you to test your de novo skills on.  The first figure is the full fragment spectrum, the spectrum is then divided into four sections to make the details easier for you to see.   Start with the high end of the spectrum, Figure 2.  We have made a pdf file for you so that you can download  the spectra and print them out so that you can get a pencil and a calculator and start sequencing.  To download the spectra, right click on the link and save the pdf document to your computer.

Once you have done your best you can proceed onto the answer page to check out the known sequence and see some of the issues we ran into with this spectrum.

Here are several hints

  1. The parent ion is m/z 636.33 which is a doubly charged ion, [M+2H]2+ .
  2. This is a tryptic peptide ending in K or R
  3. Since this is q-TOF data start by following the y ion series, try to start at the high mass end.
  4. Another note is, y ions dominate this set of q-TOF data.
  5. Mass accuracy will be on your side, mass accuracy should be better than 30 mmu, that's 0.030u.


Download the pdf of these spectra for a higher quality rendering.



Figure 1.



Figure 2.



Figure 3.



Figure 4.


Figure 5.







TOC / IS homepage









e-mail the webmaster@ionsource.com  with all inquiries
home | terms of use (disclaimer) 
Copyright � 2012 IonSource  All rights reserved. 
Last updated:  Monday, February 01, 2016 11:05:34 AM














Hit Counter