Figure 4

Inhibitory effect of NAD⁺on activities of lactate dehydrogenase (green circle) and malate/lactate dehydrogenase (orange circle) of T. thermophilus . The assay was performed at 50°C in the mixture composed of 50 mM HEPES-NaOH (pH 7.0), 0.2 mM pyruvate, 0.2 mM NADH, an appropriate amount of enzyme, and the indicated concentration of NAD⁺. After the preincubation for 2 min at 50°C, the reaction was initiated by pyruvate addition.