Table 1.
Analysis of CO dehydrogenases for FAD, metals and sulfane sulfur
| Source of CO dehydrogenase | Wild type (CO) | Wild type (H2) | E::km (H2) | F::km (H2) | G::km (H2) |
|---|---|---|---|---|---|
| FAD | 1.93 ± 0.08 | 1.98 ± 0.03 | 2.15 ± 0.06 | 1.92 ± 0.06 | 1.79 ± 0.04 |
| Mo | 1.85 ± 0.07 | 1.73 ± 0.10 | 1.95 ± 0.05 | 1.85 ± 0.03 | 1.91 ±0.08 |
| Cu | 1.62 ± 0.05 | 1.47 ± 0.03 | 0.00 ± 0.00 | 0.043 ± 0.00 | 1.48 ± 0.08 |
| ‘S’ | 1.93 ± 0.05 | 1.53 ± 0.01 | 2.0 ± 0.020 | 1.40 ± 0.13 | 2.17 ± 0.08 |
| Zn | 0.17 ± 0.01 | 0.22 ± 0.00 | 0.22 ± 0.00 | 0.076 ± 0.00 | 0.31 ± 0.01 |
Purified enzymes were obtained from O. carboxidovorans OM5 and its mutants E::km, F::km and G::km. Bacteria were cultivated under chemolithoautotrophic conditions employing a gas atmosphere of (v/v) 45 % CO, 5 % CO2, and 50 % air (referred to as “CO”) or 30 % H2, 5 % CO2, 30 % CO, and 35 % air (referred to as “H2”). All figures are in mol per mol of CO dehydrogenase determined from the absorption at 450 nm. FAD was estimated spectrophotometrically, metals by atomic absorption spectroscopy, and cyanolyzable sulfur (‘S’, sulfane sulfur) through cyanolysis. For details see “Materials and methods”. Standard deviations are based on at least three independent determinations