TABLE 4

Kinetic parameters for rifampicin hydrolase activities by recombinant AADAC and tissue microsomes

Data represent the mean ± S.D. of triplicate determinations. CLint values of human AADAC, HLM, and HJM are expressed as Vmax/Km.

SpeciesKmVmaxCLintKi
mMmM
Human
    AADAC0.2 ± 0.0149.0 ± 9.0a0.9 ± 0.1b0.3 ± 0.1
    Liver0.4 ± 0.0272.6 ± 38.5c0.7 ± 0.0d0.2 ± 0.0
    Jejunum0.3 ± 0.0211.8 ± 7.4c0.7 ± 0.0d0.7 ± 0.0
    KidneyN.D.N.D.N.D.
    LungN.D.N.D.N.D.
Rat
    AADACN.D.N.D.N.D.
    LiverN.A.N.A.0.0 ± 0.0d,e
    JejunumN.A.N.A.0.0 ± 0.0d,e
    KidneyN.A.N.A.0.0 ± 0.0d,e
    LungN.A.N.A.0.0 ± 0.0d,e
Mouse
    AADACN.D.N.D.N.D.
    LiverN.A.N.A.0.2 ± 0.0d,e
    JejunumN.D.N.D.N.D.
    KidneyN.D.N.D.N.D.
    LungN.D.N.D.N.D.

  • N.D., not detected; N.A., not applicable.

  • ↵a Vmax for AADAC is measured in pmol · min−1 · unit−1.

  • ↵b CLint for AADAC is measured in μl · min−1 · unit−1.

  • ↵c Vmax for liver, jejunum, kidney, and lungs is measured in pmol · min−1 · mg−1.

  • ↵d CLint for liver, jejunum, kidney, and lung is measured in μl · min−1 · mg−1.

  • ↵e If the Km value was relatively high, the CLint value was calculated with initial slope of the velocity versus substrate concentration.