Table 1.

Kinetic parameters^a for GalU, GalF, and double mutants GalU_T20M/R21H and GalF_M15T/H16R.

		GalU		GalUT20M/R21H		GalFM15T/H16R	GalF
		Tetramer	Monomer	Tetramer	Monomer	Monomer	Monomer
UTP	S0.5 (μM)	170 ± 20	140 ± 10	270 ± 40	250 ± 30	460 ± 40	360 ± 20
	nH	1.1 ± 0.1	1.4 ± 01	1.2 ± 0.1	1.2 ± 0.1	1.2 ± 0.1	1.4 ± 0.1
Glc-1P	S0.5 (μM)	35 ± 5	82 ± 3	2300 ± 200	2000 ± 100	750 ± 60	520 ± 60
	nH	1.2 ± 0.1	1.2 ± 0.1	1.7 ± 0.2	1.4 ± 0.2	0.95 ± 0.06	0.63 ± 0.05
Mg2+	S0.5 (μM)	2200 ± 100	2000 ± 100	2600 ± 100	2800 ± 300	2200 ± 100	3100 ± 0.1
	nH	3.7 ± 0.5	2.4 ± 0.3	2.8 ± 0.2	3.0 ± 0.2	3.3 ± 0.4	2.3 ± 0.2

^aV_max values are shown in Figure 2.