Glucuronidation is an important pathway in the biotransformation and excretion of exogenous drugs and other xenobiotics and endogenous compounds, such as bilirubin, steroid hormones, bile and fatty acids, and thyroid hormones. Conjugation with glucuronic acid generally results in the increased solubility and decreased biological activity of a compound. However, glucuronidation may be involved in the bioactivation of compounds to mutagens, carcinogens or other pharmacological active forms. UDP- glucuronosyltransferases (UGTs) are a family of enzymes responsible for glucuronidation. The present proposal focuses on the expression of human UGT cDNA in suitable host cells and characterization of the structure of the cloned protein in the absence of interfering UGTs isoenzyme. One of the principal goals will be to elucidate how the multi-substrate specificity of human UGTs are encoded in their primary and tertiary structure in order to understand the role of glucuronidation in the metabolism of endogenous substrates, drugs, and xenobiotics in humans. The project will be carried out in two laboratories (University of Arkansas and University of Nancy, France) with complementary expertise in the study of human recombinant UGTs. The studies will be applied to the following four recombinant human UGT isoenzyme; two physiologically important UGTs, UGT2B4 (hyodeoxycholic acid-specific and UGT1*1 bilirubin specific), as well as UGT*6 (small, planar phenol- specific and UGT2B10, a novel UGT of unknown substrate specificity. There are two complementary goals: (1) to synthesize human recombinant UGTs in amounts sufficient to characterize, purify, produce antibodies nd for structural studies; (2) to study the structure of human recombinant UGTs and their relationship to the functional properties of the individual isoforms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK049715-02
Application #
2414898
Study Section
Special Emphasis Panel (ZRG4-TOX-1 (01))
Program Officer
Akolkar, Beena
Project Start
1996-06-01
Project End
2000-04-30
Budget Start
1997-08-15
Budget End
1998-04-30
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Arkansas for Medical Sciences
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Little Rock
State
AR
Country
United States
Zip Code
72205
Li, Xin; Bratton, Stacie; Radominska-Pandya, Anna (2007) Human UGT1A8 and UGT1A10 mRNA are expressed in primary human hepatocytes. Drug Metab Pharmacokinet 22:152-61
Xiong, Yan; Bernardi, Dan; Bratton, Stacie et al. (2006) Phenylalanine 90 and 93 are localized within the phenol binding site of human UDP-glucuronosyltransferase 1A10 as determined by photoaffinity labeling, mass spectrometry, and site-directed mutagenesis. Biochemistry 45:2322-32
Finel, Moshe; Li, Xin; Gardner-Stephen, Dione et al. (2005) Human UDP-glucuronosyltransferase 1A5: identification, expression, and activity. J Pharmacol Exp Ther 315:1143-9
Chen, Guangping; Zhang, Daqing; Jing, Nin et al. (2003) Human gastrointestinal sulfotransferases: identification and distribution. Toxicol Appl Pharmacol 187:186-97
Radominska-Pandya, Anna; Pokrovskaya, Irina D; Xu, Jing et al. (2002) Nuclear UDP-glucuronosyltransferases: identification of UGT2B7 and UGT1A6 in human liver nuclear membranes. Arch Biochem Biophys 399:37-48
Radominska-Pandya, Anna; Chen, Guangping (2002) Photoaffinity labeling of human retinoid X receptor beta (RXRbeta) with 9-cis-retinoic acid: identification of phytanic acid, docosahexaenoic acid, and lithocholic acid as ligands for RXRbeta. Biochemistry 41:4883-90
Jude, A R; Little, J M; Bull, A W et al. (2001) 13-hydroxy- and 13-oxooctadecadienoic acids: novel substrates for human UDP-glucuronosyltransferases. Drug Metab Dispos 29:652-5
Radominska-Pandya, A; Little, J M; Czernik, P J (2001) Human UDP-glucuronosyltransferase 2B7. Curr Drug Metab 2:283-98
Radominska-Pandya, A; Chen, G; Samokyszyn, V M et al. (2001) Application of photoaffinity labeling with [(3)H] all trans- and 9-cis-retinoic acids for characterization of cellular retinoic acid--binding proteins I and II. Protein Sci 10:200-11
Jude, A R; Little, J M; Czernik, P J et al. (2001) Glucuronidation of linoleic acid diols by human microsomal and recombinant UDP-glucuronosyltransferases: identification of UGT2B7 as the major isoform involved. Arch Biochem Biophys 389:176-86

Showing the most recent 10 out of 25 publications