title: Quantitation of methylated hemoglobin adducts in a signature peptide from rat blood by liquid chromatography/negative electrospray ionization tandem mass spectrometry.
abstract: Hemoglobin adducts are often used as biomarkers for exposure to reactive chemicals in toxicology studies. Therefore, fast, sensitive, accurate, and reproducible methods for quantifying these protein adducts are key to evaluate test material dosimetry. A methodology has been developed for the quantitation of methylated hemoglobin adducts isolated from rats exposed to the model alkylating agent: methyl methane sulfonate (MMS). After 4 days of MMS exposure by oral gavage, hemoglobin was isolated from rat blood and digested with trypsin. The tryptic digestion solution was used for the adducted hemoglobin signature peptide quantitation via liquid chromatography/negative tandem mass spectrometry (LC/ESI-MS/MS). The limit of quantitation (LOQ) for the methylated hemoglobin beta chain N-terminal signature peptide (MeVHLTDAEK) was 1.95 ng/mL (5.9 pmol/mg globin). The calibration curves were linear over a concentration range of 1.95 to 625 ng/mL, with a correlation coefficient R2 >0.998, accuracy of 85.8 to 119.3%, and precision of 0.9 to 19.4%.
authors.affiliation: Toxicology and Environmental Research & Consulting, The Dow Chemical Company, 1803 Building, Midland, MI 48674, USA. fzzhang@dow.com
authors.forename: Fagen
authors.initials: F
authors.lastname: Zhang
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bartels
authors.forename: Lynn H
authors.initials: LH
authors.lastname: Pottenger
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Schisler
authors.forename: Joy J
authors.initials: JJ
authors.lastname: Grundy
authors.forename: B Bhaskar
authors.initials: BB
authors.lastname: Gollapudi
mesh_terms: D000818:Animals; D000838:Anions; D001774:Blood Chemical Analysis / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D018736:DNA Adducts / Q000737:chemistry*; D006454:Hemoglobins / Q000032:analysis*; D008297:Male; D008745:Methylation; D010455:Peptides / Q000097:blood*; D051381:Rats; D011916:Rats, Inbred F344; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000838:Anions; D018736:DNA Adducts; D006454:Hemoglobins; D010455:Peptides