Fig.1.

Kinetic characterization of the FumC and MaeB enzymes. (A) Rate of conversion of fumarate to malate by FumC, detected by the production of NADPH that is driven by the conversion of malate to pyruvate by MaeB. The concentrations were 1.7 μg ml⁻¹ FumC, 300 μg ml⁻¹ MaeB, and 2 mM NADP⁺. (B,C) Rates of conversion of malate to pyruvate by MaeB, detected by the production of NADPH. The concentrations were 44.2 μg ml⁻¹ MaeB and 4 mM NADP⁺ (B) and 40 mM malate (C). In all cases, assays were carried out in triplicate with standard error bars reported, at 32 °C, in buffers containing 10 mM Tris–SO₄ (pH 7.4), 250 mM sucrose, 2 mM MgSO₄, and 1 mM K₂SO₄.