Table 1

Kinetics of APAP glucuronidation by representative HLMs and expressed UGTs

Liver ID or Expressed UGTAcetaminophen Kinetics (20 mM UDPGA)UDPGA Kinetics (50 mM Acetaminophen)
KmVmaxnKmVmaxn
mM nmol/min/mg mM nmol/min/mg
HLM18.6  ± 1.311.7  ± 1.01.1  ± 0.01.1  ± 0.16.1  ± 0.3
HLM26.0  ± 0.55.8  ± 0.31.1  ± 0.01.1  ± 0.28.1  ± 0.71.2  ± 0.1
HLM310.0  ± 2.27.4  ± 0.91.1  ± 0.00.8  ± 0.17.4  ± 0.51.4  ± 0.1
HLM48.1  ± 0.84.0  ± 0.31.2  ± 0.01.2  ± 0.13.0  ± 0.2
HLM59.5  ± 2.13.1  ± 0.41.1  ± 0.00.9  ± 0.13.4  ± 0.21.1  ± 0.0
HLM69.6  ± 2.24.4  ± 0.51.1  ± 0.00.8  ± 0.13.5  ± 0.21.1  ± 0.0
HLM745.0  ± 10.03.1  ± 0.41.3  ± 0.12.9  ± 0.1
HLM854.5  ± 27.03.3  ± 1.20.9  ± 0.11.9  ± 0.11.2  ± 0.1
HLM910.4  ± 2.51.3  ± 0.10.9  ± 0.12.1  ± 0.11.1  ± 0.0
UGT1A19.4  ± 1.91.3  ± 0.11.6  ± 0.40.4  ± 0.11.2  ± 0.0
UGT1A62.2  ± 0.30.1  ± 0.00.2  ± 0.00.1  ± 0.0
UGT1A920.9  ± 2.16.3  ± 0.31.3  ± 0.20.5  ± 0.05.1  ± 0.1

Activities were determined using a fixed saturating UDPGA concentration with variable APAP concentrations (APAP kinetics) and a fixed saturating APAP concentration with variable UDPGA concentrations (UDPGA kinetics). Data were fit to eq. 1 or eq. 2 as described underMaterials and Methods. Shown are the parameter estimates ± S.E. of the estimates.