Table 3

Contributions of different P-450 forms toward oxazaphosphorine activation in an average human liver microsome

Enzyme PanelDrugsPredicted or Measured Activity of an Average LiverContribution by different P-450 forms
pmol/min/mg protein % of total
Human Liver MicrosomesCPA960  ± 574 3-a
LymphoblastCPA587.2 3-b
SupersomeCPA928.3 3-b 10.456.61.517.40.612.2
Human Liver MicrosomesIFA480  ± 179 3-a
LymphoblastIFA328.7 3-b 12.711.
SupersomeIFA312.7 3-b
  • 3-a Measured Mean 4-Hydroxylase Activity ± S.E.M. (n = 17 human liver microsomes).

  • 3-b Activities calculated by the RSF method using either Lymphoblast or Supersomes data as indicated.