TABLE 7.

TnrA- and GlnR-dependent gene regulation

β-Galactosidase activity was determined in extracts of cells harvested during exponential growth in glucose minimal medium containing glutamate plus casamino acids or glutamate as the respective nitrogen sources for excess and limiting nitrogen conditions. Each value is the mean of at least two independent determinations and is reproducible to within 10% (S.E.) of the mean value.

Relevant genotype	TnrA-dependent regulation; β-galactosidase activity from an amtB-lacZ fusion		GlnR-dependent regulation; β-galactosidase activity from a glnRA-lacZ fusion
	Excess nitrogen	Limited nitrogen	Excess nitrogen	Limited nitrogen
	nmol/min/mg		nmol/min/mg
Wild type	14	140	17	30
glnA(R62A)	100	83	38	34