FIG. 4.

Specific activities of key enzymes of glutamate and aspartate metabolism in P. putida KT2440 (wild type) and KTaauR mutant cells. The cells were grown to late exponential phase (A₆₀₀ = 0.6 to 0.8) in M9 medium supplemented with the indicated amino acids (10 mM each) as the sole carbon and nitrogen sources and 22 mM glucose plus the amino acids as nitrogen sources. Crude cell extracts were assayed for the specific activities (U/mg protein) of PGA, aspartase, and GDH, as described in Materials and Methods. The error bars indicate standard deviations. The means ± standard deviations were determined from at least three independent experiments.