Enzyme kinetic parameters for PFP metabolism in freshly isolated male rat hepatocytes via the formation of TFPA, TFPG, and PFPG pathways
Values were obtained from four individual reactions and two hepatocyte isolations with a total of four animals.
| Parameter | TFPA | TFPG | PFPGa |
|---|---|---|---|
| Vmax (pmol · min−1 · 106 cells−1) | 65.16 ± 5.57 | ||
| Microsome equivalent Vmax (pmol · min−1 · mg−1)b | 195.48 | ||
| Km (μM) | 0.62 ± 0.40 | ||
| Vmax/Km | 165.79 ± 128.52 μl/min/106 cells | 15.12 ± 0.82 μl pmol · h−1 · 106 cells−1c | 3.08 ± 0.47 μl · h−1 · 106 cells−1c |
| Microsome equivalent Vmax/Kmc | 497.37 μl · min−1 · mg−1 | 45.36 μl · h−1 · mg−1 | 9.24 μl · h−1 · mg−1 |
↵a PFPG was quantified by an LC-MS method using TFPG as the analytical standard.
↵b Values include contributions from spontaneous, nonenzymatic reactions.
↵c For easy comparison with Tables 1 and 2, unit was converted assuming that 1 mg of microsomal protein is equivalent to 3 million hepatocytes (Houston, 1994). Only the mean was used for this conversion.