TABLE 4

Assay of pyruvate kinase activitya

StrainCulture result (U/mg)
AnaerobicAerobic
PykFPykAPykFPykA
EB2160.72 ± 0.090.31 ± 0.030.57 ± 0.040.04 ± 0.00
EB216-ΔpykFND0.35 ± 0.05ND0.05 ± 0.00
EB216-ΔpykA0.76 ± 0.09ND0.50 ± 0.03ND
  • a U, 1 unit of pyruvate kinase generates 1 μmol pyruvate and 1 μmol ATP from PEP and ADP per minute under the test conditions (25°C, pH 7.5). mg, milligrams of crude protein extract. ND, not detectable. For anaerobic culture, the strains were grown in static 15-ml sealed BD tubes at 37°C; for aerobic culture, the strains were grown in 50-ml half-sealed BD tubes in a 220-rpm shaker at 37°C. The working volume was 10 ml in both experiments. Three repeats were performed, and the error data represent standard deviations.