Figure 2
Apparent hydrogen peroxide production in reactions containing ScLPMO10C and ScLPMO10CTR (panels A, C, D) or Cu(II)SO4 (panel B). All experiments were carried out using 1 mM ascorbic acid in 50 mM sodium phosphate buffer, pH 6.0, at 30 °C. Reaction mixtures contained 5 U/ml HRP, 100 µM Amplex Red, 1% (v/v) DMSO and varying concentrations of LPMOs and Cu(II)SO4. The data shown in panels A and C are for LPMO concentrations of 3 μM. H2O2 production rates were derived from linear progress curves (such as shown in panel C; in this experiment the signal is monitored continuously). Free copper control experiments designated as “ScLPMO10C filtrate” and “ScLPMO10CTR filtrate” in panel A were carried our using protein-free samples obtained from enzyme stock solutions by ultrafiltration. Such filtrates will contain the same amount of free copper ions as the LPMO preparations. The black bar in panel A denotes the background rate of hydrogen peroxide accumulation in the reaction containing reductant but lacking LPMO. Error bars indicate standard deviations between triplicates. The rates shown in panels A and D were obtained in independent experiments. Error bars in panel D are hidden behind the markers.
