Table 2.

Residual activity ofnac-10 mutationa

StrainChromosomal allelePlasmid allelePresence of N in mediumActivityb of:
HistidaseGDH
KC2668nac+None+28410
38965
KC2725nac-203None+31413
54436
KC2972nac-203nac++31292
46041
KC3977nac-203nac-10+35470
265141
KC4510nac-203nac-28+33397
59425
  • a Strains were grown to mid-log phase in glucose minimal medium with 0.2% (wt/vol) glutamine as the sole nitrogen source (−) or with a combination of 0.2% glutamine and 0.2% ammonium sulfate as the nitrogen source (+) and assayed for histidase and GDH (12).

  • b Specific activity is reported as nanomoles per minute per milligram of cell protein.