UGT Isoform | 1-O-CP Glucuronide Kinetics ± S.D. (n = 3) | 3-O-CP Glucuronide Kinetics ± S.D. (n = 3) | |||||||
---|---|---|---|---|---|---|---|---|---|
Kmc | Vmaxc | CLintc | Km or S50e | Vmax | CLint1 or CLmaxb | Km | Vmax | CLint2 | |
μM | pmol/min/mg protein | l/min/mg protein | μM | pmol/min/mg protein | l/min/mg protein | μM | pmol/min/mg protein | l/min/mg protein | |
Pooled HLMd | 408.2 ± 41.4 | 16.7 ± 0.6 | 0.041 | 46.0 ± 27.0d | 37.9 ± 13.0d | 0.82d | 1027 ± 129.8d | 232 ± 11.2d | 0.226d |
2B7 | 115.0 ± 14.2 | 5.4 ± 0.2 | 0.047 | 109.1 ± 5.2 | 46.9 ± 0.4 | 0.43a | |||
1A6 | <LOQ | 1557.0 ± 122.1e | 12.9 ± 0.3e | 0.008b | |||||
1A9 | <LOQ | 714.4 ± 30.2e | 41.9 ± 0.6e | 0.059b |
<LOQ, below limit of quantitation.
↵a CLint calculated from Michaelis-Menten kinetics.
↵b CLmax calculated from Hill equation fitted kinetics.
↵c Best-fit kinetic parameters for 1-O-CP glucuronide calculated with substrate inhibition equation Ksi (HLM) was 28500 ± 8200 μM and Ksi (UGT2B7) was 8090 ± 1240 μM.
↵d Best-fit Km1 and Km2 and Vmax1 and Vmax2 kinetic parameters calculated for 3-O-CP glucuronide with two-enzyme Michaelis-Menten equation.
↵e Best-fit kinetic parameters for 3-O-CP glucuronide calculated using Hill equation.