Table 2.
Kinetic parameters for published epoxide models. Karara et al. studied the incorporation of labeled free epoxide as 1-14C 14(15)-EpETrE, into phospholipids of microsomal fractions from homogenized rat livers [60]. The fraction of label in free epoxides and phospholipid-epoxides were measured by liquid scintillation for several time points over 20 min. By 20 min, the fraction of label in phospholipids was stable at about 70%, indicating a steady state. The data were digitally extracted and used to construct a mathematical compartmental model and calculate the kinetic parameters presented here (see Figure 2 for construct and model fit). The calculated recycling number is the average number of times a labeled molecule was recycled through the system [residence time/transient time −1] when entering the system from compartment 1, where residence time is −1 × (the value from the inverse matrix). CoA, coenzyme A; PL, phospholipid; PLA2, phospholipase A-2; sEH, soluble epoxide hydrolase.
| Enzyme Activity | Phospholipid Data Mean (95%CI) |
|---|---|
| Acyl-CoA Synthesis (pools/min) | 0.19 (0.16, 0.21) |
| Esterification (pools/min) | 0.82 (0.58, 1.06) |
| PLA2 Release(pools/min) | 0.065 (0.048, 0.082) |
| sEH (pools/min) | 0.0064 (−0.0046, 0.0173) |
| Residence Time in Free (min) | 157 |
| Residence Time in coA (min) | 36 |
| Residence Time in PL (min) | 450 |
| Total Time in system (min) | 643 |
| Recycling Number | 29 |