Table 1

Glucuronidation of opioid derivatives catalyzed by expressed UGT2B7

SubstrateUGT2B7YUGT2B7H
Glucuronidation Rate pmol/min/mg proteinGlucuronidation Rate pmol/min/mg protein
Morphinan Derivatives
 Normorphine80  ± 70, 3
 Norcodeine29, 245, 22
 (−) Morphine3304  ± 902152, 2580
 3-Glucuronide formation
 (−) Morphine415  ± 8384, 388
 6-Glucuronide formation
 Oxymorphone2300  ± 1253139, 2944
 Hydromorphone1550  ± 1201028, 1118
 Dihydromorphine530  ± 120617, 856
 Levorphanol25, 330, 19
 Codeine114  ± 1054, 80
 Naloxone3400  ± 3403462, 2908
 Nalorphine3400  ± 7001051, 1483
 Naltrexone1050  ± 120670, 662
 Nalmefene625  ± 110380, 412
 Naltrindole453  ± 75349, 456
 Naltriben150, 970, 0
 Nalbuphine1100  ± 110862, 758
Oripavine derivatives
 Norbuprenorphine90  ± 110, 45
 Buprenorphine280  ± 23280, 478
 Diprenorphine384  ± 34180, 257

Membrane preparations of HK293 cells stably expressing either UGT2B7Y or H were used. The assays were performed as described in the Method section. Values represent mean rates ± SEM using membranes from three different passages of cultured cells or two passages are shown. The aglycone concentrations ranged from 0.25 mM to 5 mM, concentrations which evoked rates approaching Vmax.