title: Effect of D256N and Y483D on propofol glucuronidation by human uridine 5'-diphosphate glucuronosyltransferase (UGT1A9).
abstract: Uridine 5'-diphosphate glucuronosyltransferases (UGTs) are part of a major elimination pathway for endobiotics and xenobiotics. UGT1A9 is a UGT that catalyses the conjugation of endogenous oestrogenic and thyroid hormones, acetaminophen, SN-38 (an active metabolite of irinotecan) and phenols. UGT1A9 is the only isoform that catalyses the glucuronidation of propofol (2,6-diisopropylphenol) in the liver. In the present study, we analysed polymorphisms of UGT1A9 in 100 healthy adult Japanese volunteers. A transversion of 766G > A resulting in the amino acid substitution of D256N was detected in exon 1. The allele frequency of D256N is 0.005. We investigated the effects of D256N and Y483D, which is located on the common exon of UGT1, on propofol glucuronidation by an in vitro expression study. The K(m) of wild-type, D256N and Y483D for propofol glucuronidation were 111.2, 43.6 and 64.5 microM, respectively. The V(max) of D256N and Y483D were 8.1% and 28.8%, and the efficiencies (V(max)/K(m)) were 19.1% and 57.1% of the wild-type, respectively. For mycophenolic acid, 1-naphthol and naringenin, the D256N variant lowered glucuronidation activity considerably, compared to Y483D. The V(max) value of D256N variant for mycophenolic acid was only 9.5% of the wild-type. This study shows the importance of D256N in differences between individuals concerning adverse effects of drugs that are catalysed primarily by UGT1A9. Carriers of D256N may be at risk of suffering adverse effects of propofol and other substrates that are primarily metabolized by UGT1A9.
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Shiga, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maruo
authors.forename: Asami
authors.initials: A
authors.lastname: Mori
authors.forename: Masaru
authors.initials: M
authors.lastname: Iwai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sato
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takeuchi
mesh_terms: D018686:Anesthetics, Intravenous / Q000009:adverse effects / Q000493:pharmacokinetics*; D000818:Animals; D044466:Asian People / Q000235:genetics*; D015153:Blotting, Western; D019556:COS Cells; D002522:Chlorocebus aethiops; D005787:Gene Frequency / Q000235:genetics; D014453:Glucuronosyltransferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007564:Japan; D050217:Metabolic Detoxication, Phase II / Q000235:genetics; D020125:Mutation, Missense; D009173:Mycophenolic Acid / Q000009:adverse effects / Q000493:pharmacokinetics; D020641:Polymorphism, Single Nucleotide; D015742:Propofol / Q000009:adverse effects / Q000493:pharmacokinetics*; D013379:Substrate Specificity; D014162:Transfection; D000090264:UDP-Glucuronosyltransferase 1A9
chemical_list: D018686:Anesthetics, Intravenous; C000715591:UGT1A9 protein, human; D014453:Glucuronosyltransferase; D000090264:UDP-Glucuronosyltransferase 1A9; D009173:Mycophenolic Acid; D015742:Propofol