Fig. 3.

Hydrogenation of CO₂ and H₂ evolution from formate catalyzed by the HDCR. a and b 10 µg isolated enzyme was incubated under an atmosphere of H₂ + CO₂ (80:20 [v:v], 1.1 × 10⁵ Pa) in 100 mM HEPES/NaOH, 2 mM DTE, pH 7.0 at 60 °C (a) or temperatures as indicated (b). c and d 10 µg isolated enzyme was incubated in 100 mM HEPES/NaOH, 2 mM DTE, pH 7.0 under an atmosphere of 100% N₂ and with 150 mM (c) or 50 mM (d) Na formate as substrate at 60 °C (c) or temperatures as indicated (d). H₂ production was measured in the gas phase