Fig. 5
From: Towards the understanding of the enzymatic cleavage of polyisoprene by the dihaem-dioxygenase RoxA
UV–vis spectroscopical changes of deoxygenated (oxidized) RoxA by hydrogen peroxide. a UV–vis spectra of reoxidised (deoxygenated) RoxA-Wt (black) after incubation with a tenfold stoichiometric amount of hydrogen peroxide under aerobic conditions within 15 min (black to red) and the respective difference spectra minus reoxidised RoxA. Formerly oxidised RoxA is reoxygenated in consequence of an H2O2-dependent reduction of the N-terminal haem, visible as an increase of the absorption at 540 nm and 573 nm in the difference spectrum. b UV–vis spectra of reoxidised RoxA-Wt (black) incubated with 0.1 mM pyridine under aerobic conditions for 1 h (green). Subsequently, stoichiometric amounts of H2O2 were added (red). Difference spectra of pyridine incubation minus reoxidised RoxA (orange) and pyridine + H2O2 incubation minus reoxidised RoxA (blue) indicate a pyridine-coordinated reduced haem in the sample of oxidised RoxA with H2O2 to the same extent as for RoxA-Wt as isolated (compare Fig. 1d)