title: Optimized methods for targeted peptide-based quantification of human uridine 5'-diphosphate-glucuronosyltransferases in biological specimens using liquid chromatography-tandem mass spectrometry.
abstract: The aim of this study was to optimize methods for quantifying 13 uridine 5'-diphosphate-glucuronosyltransferase (UGT) isoforms (UGT1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B10, 2B15, and 2B17) in human liver, intestinal, and kidney microsomes, and in recombinant human UGT-expressing insect cell membranes (rhUGTs) by targeted peptide-based quantification using liquid chromatography-tandem mass spectrometry. Production of targeted peptides was compared by combining three denaturing agents (urea, sodium deoxycholate, and octyl glucoside) and three denaturing temperatures (37°C, 60°C, and 95°C) followed by tryptic digestion for 2-20 hours. Denaturing conditions and digestion times yielding high production efficiency varied markedly among isoforms and specimens, indicating the importance of specific optimization. Each UGT isoform was quantified using the methods found to be optimal. The expression of 10 (1A1, 1A3, 1A4, 1A6, 1A9, 2B4, 2B7, 2B10, 2B15, and 2B17), 6 (1A1, 1A3, 1A4, 1A10, 2B7, and 2B17), and 3 (1A6, 1A9, and 2B7) isoforms was detected in human liver, intestinal, and kidney microsomes, respectively, and levels were reproducible using multiple protocols. All isoforms were quantified in rhUGTs. Determining the levels of UGTs in human tissue specimens and those in rhUGTs is important for estimating the contribution of glucuronidation to body clearance based on in vitro-in vivo extrapolation.
authors.affiliation: Drug Metabolism Research Laboratories, Astellas Pharma Inc., Yodogawa-ku, Osaka, Japan (Y.S., M.N., A.M., A.K., T.U.); Astellas Research Institute of America LLC., Skokie, Illinois (K.Te., K.Ta.).
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Sato
authors.forename: Masanori
authors.initials: M
authors.lastname: Nagata
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tetsuka
authors.forename: Kouichi
authors.initials: K
authors.lastname: Tamura
authors.forename: Aiji
authors.initials: A
authors.lastname: Miyashita
authors.forename: Akio
authors.initials: A
authors.lastname: Kawamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Usui
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D014453:Glucuronosyltransferase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007422:Intestines / Q000201:enzymology; D007527:Isoenzymes; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008861:Microsomes / Q000201:enzymology*; D010446:Peptide Fragments / Q000032:analysis*; D011489:Protein Denaturation; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007527:Isoenzymes; D010446:Peptide Fragments; C491474:UGT2B7 protein, human; D014453:Glucuronosyltransferase