FIG. 4.

Production of l-tert-leucine from trimethylpyruvate with regeneration of NADH using wild-type PTDH (▪), the 12x mutant PTDH (○), and C. boidinii FDH (▴). The small-scale batch reaction contained 300 mM ammonium trimethylpyruvate, 400 mM diammonium phosphite or ammonium formate, 0.4 mM NAD⁺, and equal amounts (by mass) of either PTDH or FDH. Samples were incubated at 40°C.