title: Strategy for identification and detection of multiple oxidative modifications within proteins applied on persulfate-oxidized hemoglobin and human serum albumin.
abstract: Oxidative stress has been suggested as an underlying mechanism of many human diseases. However, definitive evidence for this association has not been presented due to different shortcomings of the methods used to measure biomarkers of oxidative stress. Persulfates are oxidizing agents known to elicit hypersensitive reactions from the airways and skin. Despite a frequent use of persulfates at many work places, no biomarkers for persulfate exposure are available. The aim of this study was to develop a strategy for the identification and detection of multiple oxidative modifications within proteins. This strategy was applied on persulfate-oxidized proteins to identify oxidized peptides suitable for further investigation as biomarkers of persulfate exposure or oxidative stress. A strategy for the identification and the relative quantification of multiple oxidative modifications within proteins was developed. The usage of two software packages facilitated the search for modified peptides to a great extent. Oxidized peptides were relatively quantified using liquid chromatography/tandem mass spectrometry in selected reaction monitoring mode. The result showed that persulfates oxidize tryptophans and methionines resulting in mass shifts of 16 and/or 32 Da. Also, oxidized albumin peptides in nasal lavage fluid samples from subjects challenged with persulfate were detected. The oxidation degree before and after challenge remained constant for peptides containing methionine sulfoxide. For peptides containing oxidized tryptophan the oxidation degree increased after exposure. Some of these oxidized peptides may be suitable as biomarkers; however, further evaluation is required.
authors.affiliation: Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund, Lund University, SE-221 85 Lund, Sweden. harriet.mortstedt@med.lu.se
authors.forename: Harriet
authors.initials: H
authors.lastname: Mörtstedt
authors.forename: Marina C
authors.initials: MC
authors.lastname: Jeppsson
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ferrari
authors.forename: Bo A G
authors.initials: BA
authors.lastname: Jönsson
authors.forename: Monica H
authors.initials: MH
authors.lastname: Kåredal
authors.forename: Christian H
authors.initials: CH
authors.lastname: Lindh
mesh_terms: D015415:Biomarkers / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004781:Environmental Exposure / Q000032:analysis; D005260:Female; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007536:Isomerism; D013058:Mass Spectrometry; D008715:Methionine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D017817:Nasal Lavage Fluid / Q000737:chemistry; D010084:Oxidation-Reduction; D010446:Peptide Fragments; D017680:Potassium Compounds / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D012984:Software; D013431:Sulfates / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism; D014364:Tryptophan / Q000737:chemistry / Q000378:metabolism
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D010446:Peptide Fragments; D017680:Potassium Compounds; D012709:Serum Albumin; D013431:Sulfates; C009007:potassium persulfate; D014364:Tryptophan; D008715:Methionine; D014357:Trypsin; C013111:methionine sulfoxide