. 2001 Oct;67(10):4458–4463. doi: 10.1128/AEM.67.10.4458-4463.2001

TABLE 1.

Comparison of biosynthesis assay kinetic parameters for glutamine synthetase enzymes from different sources

Enzyme source	Organism characteristic(s)	Cation	K_m (mM)			V_β-glutamate/V_α-glutamate at substrate concn of^a:
Enzyme source	Organism characteristic(s)	Cation	α-Glu	β-Glu	ATP	100 mM	200 mM
Archaea
Methanohalophilus portucalensis	Mesophile; halophile	Mg²⁺	104 ± 20	175 ± 50	6 ± 2	0.14	0.17
Methanococcus jannaschii	Hyperthermophile; halotolerant	Mg²⁺	58 ± 8^b	>200^b		0.04	0.016
Archaeoglobus fulgidus	Hyperthermophile; halotolerant	Mn²⁺	3.0^c	—^d	0.56^c	0.08	0.052
Pyrococcus KOD1	Hyperthermophile; halotolerant	Mg²⁺	23.5^e		28.0^e
Halobacterium salinarium	Halophile	Mg²⁺	49^f		0.59^f
Bacteria
Bacillus subtilis	Mesophile	Mn²⁺	0.5^g	>100	0.4^g		0.003
Bacillus licheniformis	Mesophile	Mn²⁺	3.6^h		0.9^h
Escherichia coli	Mesophile	Mg²⁺	2.4ⁱ		0.68ⁱ		4 × 10⁻⁶
Nitrobacter agilis	Mesophile	Mg²⁺	6.3^j
Eukaryotes
Sheep brain		Mg²⁺				0.18 (NH₃)^k
						0.46 (NH₂OH)^k
Rat liver		Mg²⁺				0.18 (NH₃)^k
						0.28 (NH₂OH)^k

Ratio of GS specific activity toward β-glutamate compared to that toward α-glutamate for each substrate at 100 and 200 mM.

Determined at 60°C.

H. Schreier, unpublished results.

Observed substrate inhibition at >75 mM β-glutamate prevented any estimate of K_m.

Rahman et al. (15).

Manitz and Holldorf (11).

Schreier et al. (20); Wedler et al. (22).

Donohoe et al. (6).

ⁱ

Woolfolk et al. (23).

Kumar and Nicholas (9).

Pruisner and Stadtman (14).