Fig. 2

Spectral analysis. a UV/Vis spectra of oxidized (red, dashed line) and reduced (blue, solid line) PcCDH_Tr (70 µM). For obtaining the reduced spectrum, 1 mM cellobiose was added to the purified enzyme solution in 50 mM sodium acetate buffer, pH 4. Inset: Magnification of the spectrum between 500 and 600 nm to show the heme b α- and β-peak in more detail. b UV/Vis spectrum of the supernatant after trichloroacetic acid precipitation of PcCDH_Tr for determining the FAD occupancy. The wavelengths 280 and 450 nm are marked with vertical lines and show the contribution of the FAD cofactor to the molar absorption coefficient at 280 nm used for the calculation of the protein concentration