Vmax/Km values of PFP metabolism in male and female rat, mouse, dog, and human microsomes and cytosol via GSH S-conjugation pathway
| Metabolite | Vmax/Kma | |||||||
|---|---|---|---|---|---|---|---|---|
| Rat | Mouse | Dog | Human | |||||
| Male | Female | Male | Female | Male | Female | Male | Female | |
| μl · h−1 · mg−1 | ||||||||
| TFPG, microsome | 32.47 ± 4.49 | 50.45 ± 4.33 | 13.64 ± 0.67 | 5.53 ± 1.29 | 13.02 ± 1.46 | 10.15 ± 0.95 | 35.54 ± 1.18 | 30.14 ± 1.23 |
| TFPG, cytosol | 1.38 ± 0.48 | 1.98 ± 0.72 | 2.85 ± 0.86 | 1.64 ± 0.47 | 2.44 ± 0.77 | 2.31 ± 1.07 | 3.91 ± 1.06 | 6.32 ± 0.08 |
| PFPG, microsomeb | 3.34 ± 0.56 | 3.48 ± 0.52 | 2.24 ± 0.21 | 0.54 ± 0.71 | 1.58 ± 0.46 | 0.97 ± 0.26 | 1.95 ± 0.04 | 1.93 ± 0.26 |
| PFPG, cytosolb | 4.72 ± 0.74 | 3.61 ± 0.66 | 5.32 ± 0.73 | 5.32 ± 0.64 | 1.65 ± 0.17 | 1.95 ± 0.45 | 4.63 ± 0.23 | 5.90 ± 0.32 |
↵a Intrinsic clearance as a result of enzymatic reaction. Clearance rates from nonenzymatic, spontaneous reactions were obtained from heat-inactivated microsomes or cytosol and were subtracted from the rates obtained in liver microsomes or cytosol. Values were averaged from the V/[S] ratios at one to four different PFP concentrations that are low relative to the Km and were from at least three individual enzymatic reactions. The enzymatic reaction was conducted with microsomal and cytosol protein concentrations at 0.2 and 0.5 mg/ml, respectively, and incubated for 60 min in 0.1 M potassium phosphate buffer (pH 7.4) in the presence of 10 mM GSH at 37°C.
↵b PFPG was quantified by an LC-MS method using TFPG as the analytical standard.