title: Multiple proteases to localize oxidation sites.
abstract: Proteins present in cellular environments with high levels of reactive oxygen and nitrogen species and/or low levels of antioxidants are highly susceptible to oxidative post-translational modification (PTM). Irreversible oxidative PTMs can generate a complex distribution of modified protein molecules, recently termed as proteoforms. Using ubiquitin as a model system, we mapped oxidative modification sites using trypsin, Lys-C, and Glu-C peptides. Several M+16 Da proteoforms were detected as well as proteoforms that include other previously unidentified oxidative modifications. This work highlights the use of multiple protease digestions to give insights to the complexity of oxidative modifications possible in bottom-up analyses.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, United States of America.
authors.forename: Liqing
authors.initials: L
authors.lastname: Gu
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, United States of America.
authors.forename: Renã A S
authors.initials: RA
authors.lastname: Robinson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D008715:Methionine / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010447:Peptide Hydrolases / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D059748:Proteolysis; D040901:Proteomics; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D025801:Ubiquitin; D008715:Methionine; D010447:Peptide Hydrolases