TABLE 2.

NAC^WT and NAC^NC activities at various NAC-dependent targets

Plasmida	Sp act (nmol of product formed/min/mg of protein)b
	Urease		Histidase		GDH		GOGAT		β-Galacto- sidase
	+N	−N	+N	−N	+N	−N	+N	−N	+N	−N
None	23	167	46	45	916	980	112	207	7	9,890
pCB1289	19	1,070	33	533	863	42	102	36	8	2,160
pCB1305	35	1,680	35	370	942	309	147	108	6	2,740

^aThe strain background was KC4727 (hutC515, Δ[bla-2], nac-204::λplacMu53). pCB1289 contains wild-type nac (expression from the native nac promoter), and pCB1305 is identical, except that it contains the NAC^NC mutant NAC^L111K.

^bEach value is the average of at least three separate experiments with a standard error of ≤15% of the mean. The media were W4 minimal salts (18) supplemented with 0.4% glucose, 0.2% ammonium sulfate, and 0.2% glutamine (+N) or glucose and 0.04% glutamine (−N). (In addition, ampicillin was present at 100 μg/ml when a plasmid was present in the strain.) The β-galactosidase values reflect the expression of the chromosomal nac promoter.