Table 3.
Comparison of literature values of the peroxide turnover parameters of various bacterial diheme cytochrome c peroxidases in the semi-reduced state using cytochromes c as an electron donor.
| Organism ‡ | Km (μM) for H2O2 | kcatobs (s−1) | Electron donor (concentration) | kcatobs/[ED] (s−1μM−1)& | Required Pre-reduction? | Reference |
|---|---|---|---|---|---|---|
| Psa | 6 | 118 | Psa cyt 551 (13 μM) | 14 | Yes | (24) |
| Rc* | 33 | 40 | Rc cyt c2 (18 μM) | 2 | Yes | (34) |
| Pss | 1.8 | 88 | Pss cyt c551 (7 μM) | 13 | Yes | (17) |
| Gs | 6.2 | 15.5 | ABTS (3 mM) | Yes | (18) | |
| Mc | 0.5 | 50 | Mc cyt c555 (9 μM) | 5 | No | (20) |
| So | 0.3 | 73 | So cyt c5 (4 μM) | 18 | Yes | This Study |
‡
Abbreviations match those used in the text.
*
Turnover for as-isolated protein.
&
This approximation holds because the concentration of electron donor is much less than the estimated Km, therefore the rate is approximately linear with electron donor concentration.