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Isobaric Labelling

Proteins are labelled with isobaric tags to allow for quantification of relative and absolute amounts from different sources, in a single experiment

Platform Mass spectrometry
  • Analytical report
Research Objectives The identification of proteins and their relative abundance
Related Services
  • Label-free profiling


Proteins are differentially expressed under various conditions, for example healthy and diseased states. Isobaric tags for relative and absolute quantitation (iTRAQ) is a non-gel-based technique used to quantify proteins from different sources. iTRAQ-based quantitation can measure differences in the proteome under varying conditions. These differences can then be used for the identification of potential biomarkers.

Service Details

At the CPGR our chemical labelling approach uses iTRAQ chemistry to attach reporter ions to peptides derived from tryptic digestion. iTRAQ labels are available in 4-plex and 8-plex format allowing researchers to compare up to 8 different conditions. Protein samples supplied are digested and labelled prior to two-dimensional chromatography. Fractionated protein is then analysed by tandem mass spectrometry (LC-MS). Labelled peptides are identified through a database search allowing for the identification of the corresponding protein. Quality control measures include an exogenous spike in the extraction buffer and another exogenous spike prior to digestion and labelling.

Service Deliverables

An analytical report is provided detailing the experimental steps taken to establish protein identity and differential regulation. Protein identity and regulatory information is included.

Starting Material

  • Samples can be provided as either extracted protein or as tissue. Please contact us prior to extraction or tissue submission to confirm that the appropriate protocols are available.