What Is the Exact Mass that iTRAQ® Reagents Add to Peptides?


Date: 12/18/2019
Categories: iTRAQ Reagent

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For research use only. Not for use in diagnostic procedures.


Answer

There are two types of iTRAQ® Reagent kits, 4plex and 8plex; these kits contain isobaric tags that derivatize amine groups for relative and absolute quantification of proteins and peptides.

1) iTRAQ reagents in the 4plex kit: These reagents are numbered 114, 115, 116 and 117, and they add a mass of 145 Da. The exact monoisotopic masses of each reagent can be found on www.unimod.org, and these are calculated from the most abundant natural isotope of each constituent element:

  • Reagent 114 adds 144.105918 Da
  • Reagent 115 adds 144.099599 Da
  • Reagents 116 and 117 add 144.102063 Da
2) iTRAQ reagents in the 8plex kit: These reagents are numbered 113, 114, 115, 116, 117, 118, 119, and 121, and they add a mass of 304 Da. The monoisotopic mass of each 8plex reagent are shown below:
  • Reagents 113, 114, 116 & 117 add 304.205360 Da
  • Reagents 115, 118, 119 &121 add 304.199040  Da
Note that corresponding 4plex and 8plex reagents (e.g., 113 from the 4plex kit and 113 from the 8plex kit) are different reagents and have different masses.