TABLE 3

Equilibrium hydrogen partial pressures produced by the NADH-dependent [FeFe]-hydrogenase Hyd1ABC at different pH values and NADH/NAD+ ratiosa

ConditionNADH/NAD+ ratioMean (range) hydrogen partial pressure (Pa)Hydrogen produced (nmol)
pH 6.5, 2.0 mM NAD+, 3.0 mM NADH1.540.0 (6.9)95.4
pH 6.5, 2.5 mM NAD+, 2.5 mM NADH1.021.8 (8.7)51.8
pH 7.0, 2.0 mM NAD+, 3.0 mM NADH1.525.9 (0.8)61.9
pH 7.0, 2.5 mM NAD+, 2.5 mM NADH1.017.0 (11.3)40.4
  • a Assays were performed in 6.5-ml serum bottles with 0.5 ml of liquid volume containing 0.86 μg of protein and 6 ml of headspace.