Kinetics of D2 metabolism in phosphatidylcholine vesicles
Kinetic constants were determined in vesicles prepared from dioleoyl phosphatidylcholine and cardiolipin. Values for Km and kcat are mean ± S.E. from the hyperbolic curve fitted to the data from a single experiment by least-squares nonlinear regression using KaleidaGraph 3.6 (Synergy Software).
Substrates | Km | kcat | kcat/Km |
|---|---|---|---|
| mol/mol PL | mol/min/mol P450scc | (mol/mol PL)-1 min-1 | |
| Cholesterol | 0.21 ± 0.04 | 46 ± 5 | 219 |
| D2 | 1.65 ± 0.61 | 5.62 ± 1.73 | 3.4 |
| 20(OH)D2 | 0.055 ± 0.007 | 1.99 ± 0.11 | 36.2 |
| 17,20(OH)2D2 | 0.057 ± 0.022 | 0.21 ± 0.04 | 3.7 |