- ITRAQ
iTRAQ (isobaric tag for relative and absolute quantitation) is a non-gel based technique used to identify and quantify
protein s from different sources in one single experiment. It usesisotope coded covalent tags. iTRAQ is used inproteomics to study quantitative changes in the proteome.cite journal |author=Zieske LR |title=A perspective on the use of iTRAQ reagent technology for protein complex and profiling studies |journal=J. Exp. Bot. |volume=57 |issue=7 |pages=1501–8 |year=2006 |pmid=16574745 |doi=10.1093/jxb/erj168] cite journal |author=Gafken PR, Lampe PD |title=Methodologies for characterizing phosphoproteins by mass spectrometry |journal=Cell Commun. Adhes. |volume=13 |issue=5-6 |pages=249–62 |year=2006 |pmid=17162667 |doi=10.1080/15419060601077917]Procedure
The method is based on the covalent labeling of the
N-terminus andsidechain amine s ofpeptide s from protein digestions with tags of varying mass. There are currently two mainly used reagents: 4-plex and 8-plex, which can be used to label all peptides (In theory) from different samples/treatments. These samples are then pooled and usually fractionated by nanoliquid chromatography and analyzed by tandemmass spectrometry (MS/MS). A database search is then performed using thefragmentation data to identify the labelled peptides and hence the corresponding proteins. The fragmentation of the attached tag generates a low molecular mass reporter ion that can be used to relatively quantify the peptides and the proteins from which they originated, using software such as the freely available i-Trackercite journal |author=Shadforth IP, Dunnley PJ, Lilley KS, Bessant C |title=i-Tracker: For quantitative proteomics using iTRAQ |journal=BMC Genomics |volume=6 |pages=145 |year=2005 |doi=10.1186/1471-2164-6-145] .See also
*
SILAC External links
* [http://www.proteome.soton.ac.uk/iTRAQ.htm Centre for Proteome Research]
References
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