title: Proteolytic 18O-labeling strategies for quantitative proteomics.
abstract: A number of proteomic techniques have been developed to quantify proteins in biological systems. This review focuses on the quantitative proteomic technique known as "proteolytic 18O-labeling." This technique utilizes a protease and H(2)18O to produce labeled peptides, with subsequent chromatographic and mass spectrometric analysis to identify and quantify (relative) the proteins from which the peptides originated. The technique determines the ratio of individual protein's expression level between two samples relative to each other, and can be used to quantitatively examine protein expression (comparative proteomics) and post-translational modifications, and to study protein-protein interactions. The present review discusses various aspects of the 18O-labeling technique, including: its history, the advantages and disadvantages of the proteolytic 18O-labeling technique compared to other techniques, enzymatic considerations, the problem of variable incorporation of 18O atoms into peptides with a discussion on recent advancements of the technique to overcome it, computational tools to interpret the data, and a review of the biological applications.
authors.affiliation: Case Center for Proteomics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA. masaru.miyagi@case.edu
authors.forename: Masaru
authors.initials: M
authors.lastname: Miyagi
authors.forename: K C Sekhar
authors.initials: KC
authors.lastname: Rao
mesh_terms: D020869:Gene Expression Profiling / Q000379:methods*; D007553:Isotope Labeling / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods*; D010103:Oxygen Isotopes / Q000737:chemistry*; D010447:Peptide Hydrolases / Q000737:chemistry*; D010449:Peptide Mapping / Q000379:methods*; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D010103:Oxygen Isotopes; D020543:Proteome; D010447:Peptide Hydrolases