Table 1.

Repression of nitrate reductase in anareAΔ2-389 strain

Relevant genotypeaNitrate reductase sp act for strain grown in presence ofb:Derepression (%)c
20 mM NO320 mM NO3 + 40 mM NH4+
Wild type (areA+)144 ± 9.09.7 ± 2.66.7
areAΔ2-389122 ± 6.63.9 ± 1.13.2
areAΔ868-876101 ± 9.056.2 ± 1.255.6
  • a The full genotypes of theareA+, areAΔ2-389, andareAΔ868-876 strains are pabaA1(p-aminobenzoate requiring), yA2 (yellow conidial color) pabaA1 areAΔ2-389, andareAΔ868-876 pantoB100 (d-pantothenate requiring) fwA1 (fawn conidial color), respectively.areAΔ868-876 has been described previously (13).

  • b Growth and assay conditions were as described in reference 13. Specific activities are presented as nanomoles of NO2 produced per minute per milligram of protein (means ± standard deviations).

  • c Calculated by dividing the specific activity on NO3 + NH4+ by that on NO3 and expressing it as a percentage.