Table 2.

Model validations using knockout mutants

A
	Changes in GS when cells are transferred to an ammonia-limiting medium
Cell type	Experiment	Simulation
Wild type	++	++
ΔglnG (ΔNRI)	±	±
ΔglnL (ΔNRII)	±	±
ΔglnD (ΔUTase/UR)	++	+
ΔglnB (ΔPII)	±	±
ΔglnK (ΔGlnK)	++	++

B
	The GS concentration of mutants is compared with that of a wild type in the ammonia-rich medium
Mutant	Experiment	Simulation
ΔglnL (ΔNRII)	+	+
ΔglnD (ΔUTase/UR)	–	–
ΔglnB (ΔPII)	++	++
ΔglnK (ΔGlnK)	±	±

The GS concentrations of a wild-type and knockout mutants were simulated in an ammonia-limiting or ammonia-rich medium to compare with those of experimental data.

(A) The GS concentrations were compared between an ammonia-rich medium and an ammonia-limiting medium, where a wild type greatly increased the GS concentration due to the Ntr response. When the cells were transferred from an ammonia-rich medium to an ammonia-limiting medium, the GS concentration increased more than five-fold (++), increased five- to two-fold (+), and hardly changed (less than two-fold) (±). (B) The GS concentrations of the mutants were compared with those of a wild type in an ammonia-rich medium. Compared with the wild type, the GS concentration of mutants increased five-fold (++), increased five- to two-fold (+), hardly changed (±), and decreased (–).