Table 4

Glucuronidation of xenobiotics catalyzed by expressed human UGT1A3

SubstrateGlucuronide Formation
pmol/min/mg of protein
 4-Methylumbelliferone400  ± 70
 Scopoletin1970  ± 300
 Naringenin (0.2 mM)612  ± 59
 Apigenin (0.2 mM)508  ± 17
 Quercetin (0.2 mM)550
 Anthraflavic acid608
Phenolic compounds
 4-Nitrophenol239  ± 19
Carboxylic acids
 Valproic acid9
 Decanoic acid80
 Dodecanoic acid114
Aliphatic alcohols
  • Assays were performed in pH 7.5 Tris buffer at 37°C for 0.25–1.0 hr, using whole-cell homogenates of HK293 cells expressing UGT1A3. The concentration of UDP-glucuronic acid was 2.0 mM, and the aglycone concentrations were 0.5 mM, unless otherwise noted. Enzymatic rates are expressed as the mean ± SD of determinations from three transfections or the average determinations using cell homogenates from two transfections.

  • 4-a ND, glucuronide formation was not detected (limits of detection, 2.0 pmol/min/mg of protein).