Table 3. Apparent Steady State Parameters of NagOx^a.

	wild-type NagOx			Leu251Arg NagOx
substrate	K′M (mM)	k′cat (s–1)	k′cat/K′M (M–1 s–1)	K′M (mM)	k′cat (s–1)	k′cat/K′M (M–1 s–1)
N-acetyl-d-glucosamine	0.22 ± 0.04	140 ± 6	64 × 104	23 ± 6	34 ± 3	1.5 × 103
N-acetyl-d-galactosamine	0.13 ± 0.02	120 ± 4	93 × 104	1.9 ± 0.6	4.2 ± 0.4	2.2 × 103
d-glucose	92 ± 15	2.2 ± 0.1	23	6.2 ± 2.5	1.3 ± 0.2	210
d-galactose	30 ± 8	2.3 ± 0.02	77	7.7 ± 1.8	2.1 ± 0.2	270
d-mannose	36 ± 5	0.71 ± 0.03	20	14 ± 4	5.3 ± 0.5	390
N,N′-diacetylchitobiose	8.5 ± 2.2	36 ± 4	4 × 103	52 ± 4	2.7 ± 0.1	52
d-cellobiose	130 ± 40	0.22 ± 0.03	2	80 ± 26	3.2 ± 0.6	40
d-maltose	>400	<0.2	0.5	22 ± 4	0.7 ± 0.1	34
maltotriose	nd	nd	–	210 ± 30	0.34 ± 0.02	1.6

^aThe kinetic parameters were measured at 25 °C in 50 mM KP_i (pH 7.5). nd indicates no activity could be measured.