Mascot: The trusted reference standard for protein identification by mass spectrometry for 25 years

Exercise SQ1


A simple sequence tag search


User access to any Mascot server, including the Matrix Science public web site


The sample was digested with trypsin and analysed on a ESI-QUAD-TOF. A tag has been interpreted from one of the MS/MS spectra. Precursor m/z is 738.25 with charge 2+. Residue code i means I or L and q means Q or K. Search Swiss-Prot with precursor and fragment mass tolerances of 0.5 Da

sequence tag


  • Although the screen shot comes from Distiller, you should not submit your searches from Distiller. The aim of this exercise is to understand how to use the sequence tag syntax and web-browser search form
  • You should be able to get a strong match using a standard sequence tag


  1. What is the peptide sequence?


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