title: The Isotope-Coded Affinity Tag Method for Quantitative Protein Profile Comparison and Relative Quantitation of Cysteine Redox Modifications.
abstract: The isotope-coded affinity tag (ICAT) technique has been applied to measure pairwise changes in protein expression through differential stable isotopic labeling of proteins or peptides followed by identification and quantification using a mass spectrometer. Changes in protein expression are observed when the identical peptide from each of two biological conditions is identified and a difference is detected in the measurements comparing the peptide labeled with the heavy isotope to the one with a normal isotopic distribution. This approach allows the simultaneous comparison of the expression of many proteins between two different biological states (e.g., yeast grown on galactose versus glucose, or normal versus cancer cells). Due to the cysteine-specificity of the ICAT reagents, the ICAT technique has also been applied to perform relative quantitation of cysteine redox modifications such as oxidation and nitrosylation. This unit describes both protein quantitation and profiling of cysteine redox modifications using the ICAT technique.
authors.affiliation: Department of Pharmacy, National University of Singapore, Singapore.
authors.forename: James Chun Yip
authors.initials: JCY
authors.lastname: Chan
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Pharmacy, National University of Singapore, Singapore.
authors.forename: Eric Chun Yong
authors.initials: ECY
authors.lastname: Chan
mesh_terms: D003545:Cysteine / Q000032:analysis* / Q000737:chemistry*; D007553:Isotope Labeling / Q000379:methods*; D010084:Oxidation-Reduction; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D003545:Cysteine
keywords: cysteine thiol modification; isotope-coded affinity tag (ICAT); liquid chromatography; quantitative protein profiling; redox proteomics; tandem mass spectrometry