Fig. 3: Properties of the purified Hyd-1h at a range of conditions.

a, b Relative specific activity (in % of the optimum activity) of the isolated hydrogenase (Hyd) and the control without enzyme (NC) within a temperature range of 30 to 100 °C (a) and within a pH range of 4 to 10 at 50 °C (b). c Circular dichroism spectrum from 200 to 260 nm measured after 1, 30, and 60 min incubation at 95 °C in 20 mM phosphate buffer (pH 7.0). d Residual activity (% of activity prior to heating) of the enzyme at 50 °C after incubation for 30 min at 70, 80, or 85 °C. Error bars indicate standard deviations (n = 3).