The incubation system consisted of 50 mM Tris-HCl buffer (pH 7.4), 0.25 mg/ml proteins (HLMs, HIMs, HKMs, or UGTs), 25 [micro]g/ml alamethicin, 8 mM Mg[Cl.sub.2], 1 mM UDPGA, and 5, 20, 50, or 200 [micro]M WEL in a total volume of 200 [mciro]l.
Thus, the glucuronidation of WEL in HLMs, pooled HIMs, and pooled HKMs were initially investigated prior to identifying the metabolic enzymes.
Given that UGT1A9 is highly expressed in human kidney, HKMs share similar behavior with UGT1A9 in WEL glucuronidation.