Table 1

Glucurnidation of amines catalyzed by expressed human UGT1A3

SubstrateGlucuronide Formation
pmol/min/mg of protein
Primary amines
 α-Naphthylamine12  ± 2
 β-Naphthylamine15  ± 3
 2-Aminobiphenyl11  ± 1
 4-Aminobiphenyl77  ± 9
Secondary amines
 Diphenylamine12  ± 4
Tertiary amines
 Imipramine6  ± 1
 Amitriptyline38  ± 5
 Cyproheptadine87  ± 10
  • Assays were performed at pH 8.4 and 37°C for 2.0 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. Enzymatic rates are expressed as the mean ± SD of determinations from three different transfections or the average determinations from two transfections.

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