TABLE 3.

Residual gltA expression in the absence of GltC and TnrA^a

Strain	Genotype	gltA-gltC region of fusion	β-Galactosidase activity, Miller units (gltA-lacZ fusion)
			Ammonium	Ammonium + glutamate	Glutamate
BB1045	gltC gltAp3	Wild type	1.9	0.9	0.3
BB1082	gltC gltAp3	gltAp3	18.6	10.5	2.5
BB1083	gltC gltAp3 tnrA	gltAp3	20.2	12.7	10.7

^aThe various strains, derivatives of SX150103, were grown to mid-exponential phase in the indicated glucose minimal medium and assayed for β-galactosidase activity.