Amino acid positions 69–132 of UGT1A9 are involved in the C-glucuronidation of phenylbutazone
Section snippets
Chemicals
7-Hydroxy-(4-trifluoromethyl) coumarin (HFC) glucuronide, PB and UDPGA were purchased from Sigma–Aldrich (St. Louis, MO). HFC was purchased from Kanto Chemicals Co. (Tokyo, Japan). Bac-to-Bac baculovirus expression system, Cellfectin transfection reagent, SF900 II and Sf9 cells were purchased from Invitrogen (Carlsbad, CA). Anti-UGT1A antibody (WB-UGT1A) was purchased from BD Gentest (Woburn, MA). ECLTM advance Western blotting detection kit was purchased from GE Healthcare (Piscataway, NJ).
Expression of chimeric and wild type UGT proteins
Expression level of each protein in Sf9 microsomes was determined (Fig. 2). Relative expression levels of UGT1A9, UGT1A9(1–68)/1A8(69–286), UGT1A9(1–132)/1A8(133–286), UGT1A9(1–212)/1A8(213–286), UGT1A8(1–68)/1A9(69–286), UGT1A8(1–132)/1A9(133–286), UGT1A8(1–212)/1A9(213–286), UGT1A8(1–68)/1A9(69–132)/1A8(133–286), UGT1A9(1–68)/1A8(69–132)/1A9(133–286) and UGT1A8 were 1, 1.2, 1.5, 3, 1.5, 1.6, 1.8, 1.7, 0.9 and 2.5, respectively. All enzymatic activities expressed in this paper have been
Discussion
We recently reported that UGT1A9 catalyzes PB C-glucuronidation [10]. After that report, Kerdpin et al. [22] also revealed that sulfinpyrazone, a derivative of PB, is C-glucuronidated by mainly UGT1A9 and, to a minor extent, by UGTs 1A7 and 1A10. From these results, the question arose as to why despite UGTs 1A7, 1A8, 1A9 and 1A10 having high amino acid sequence identity with each other, only UGT1A8 did not show PB and sulfinpyrazone C-glucuronidating activity. In the present study, to
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Interaction between oxidative stress sensor Nrf2 and xenobiotic-activated aryl hydrocarbon receptor in the regulation of the human phase II detoxifying UDP-glucuronosyltransferase 1A10
2010, Journal of Biological ChemistryCitation Excerpt :UGT1A9 is the only isoform within the UGT1A7–10 gene cluster, which is expressed in the liver. It is also highly expressed in kidneys and catalyzes the glucuronidation of estragole, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and compounds such as phenylbutazone (16–18). The signal transduction pathways responsible for sensing oxidative stress and activating the appropriate defense genes are still not completely understood in eukaryotes.