DOI: 10.1128/JB.185.10.3210-3213.2003
Article Figures & Data
Figures
- FIG. 1.
Electron paramagnetic resonance spectra of P. chloritidismutans chlorate reductase. The enzyme concentration was 2.3 mg/ml or 14 μM. Trace A is from the enzyme isolated anaerobically; trace B is from dithionite-reduced enzyme. The amplification for trace B is 25 times that for trace A. Electron paramagnetic resonance conditions: microwave frequency, 9.43 GHz; microwave power, 126 mW; modulation frequency, 100 kHz; modulation amplitude, 0.63 mT; temperature, 16 K.
Tables
- TABLE 1.
Summary of the purification of chlorate reductase from P. chloritidismutans
Step Vol (ml) Protein concn (mg/ml) Total activity (U) Sp act (U/mg) Yield (%) Purification (fold) Soluble fraction 13 27.5 726 2 100 1 Q-Sepharose 20 2.8 335 6 46.1 3 Hydroxyapatite 5 3.5 155 8.7 21.4 4.4 Mono-Q 2 3.3 95 14.4 13.1 7.2 Superdex 200 10 0.18 75 42 10.3 21 - TABLE 2.
Summary of enzyme characteristics
Enzyme Localization Electron acceptor(s) Subunits (kDa) Native enzyme composition EPR of Mo(V) (g values) ClO3− Vmax (U/mg) Km (μM) P. mirabilis chlorate reductase C Membrane Chloratea 75, 63, 56 Heterotrimer (α1β1γ1) GR-1 (per)chlorate reductase Periplasm Perchlorate, chlorate, nitrate, iodate, bromate 95, 40 Trimers of heterodimers (α3β3) 2.002, 2.017 13.2 <5 P. chloritidismutans chlorate reductase Cytoplasm Chlorate, bromateb 97, 38, 34 Heterotrimer (α1β1γ1) 2.002, 2.024, 2.076 51.3 159 - TABLE 3.
Localization of chlorate reductase, chlorite dismutase, and catalase activity in cell fractions of strain AW-1
Fraction ClO3− reductase (U/mg) ClO3− reductase (U total) ClO2− dismutase (U/mg) ClO2− dismutase (U total) Catalase (U/mg) Catalase (U total) Periplasmic 6.2 7.5 236 284 NAa NA Cytoplasmic 29.6 47.2 20.6 32.7 15.7 24.9 Membrane 3.8 2 9.3 4.8 3.3 1.7 ↵ a NA, no activity.
