Table 1. Effect of ionic strength on the position of spin equilibrium in CYP261 species*.
| P450 species |
Fh(0), %a | ΔFh, %b | Kion, mMc |
|---|---|---|---|
|
| |||
| 261C1(−) | 62.6 ± 1.9 | 19.4 ± 5.9 | 832 ± 89 |
| 261C1(+) | 61.2 ± 2.8 | 23.1 ± 8.7 | 150 ± 89 |
| 261C2 | 74.7 ± 10.8 | 6.0 ± 4.2 | 89 ± 49 |
| 261D1(−) | 58.0 ± 10.6 | −15.0 ± 3.4 | 163 ± 52 |
| 261D1(+) | 72.6 ± 2.6 | −13.2 ± 4.1 | 138 ± 42 |
*
The values given in the table represent the averages of 2-4 individual measurements, and the “±” values show the confidence interval calculated for p = 0.05.
a
P450 high-spin content in cytochrome P450 extrapolated to zero ionic strength (see equation (1)).
b
Maximal amplitude of the change in the content of the P450 high spin state induced by an increase in ionic strength.
c
Apparent equilibrium constant of ion binding to a putative ion binding site found by approximation of the ionic strength dependencies with equation (1).