TABLE 1.

Steady-state kinetic parameters of MshB mutants

MshBa,b	Km	kcat	kcat/Km	WT activity
	mm	min−1	m−1s−1	%
WTc	38 ± 4	46 ± 2	20 ± 1
D15A	52 ± 11	0.29 ± 0.02	0.09 ± 0.01	0.5
Y142A	22 ± 2	1.8 ± 0.05	1.36 ± 0.10	6.8
Y142F	9 ± 0.5	0.57 ± 0.01	1.05 ± 0.05	5.3
Y142Q	17 ± 2	1.2 ± 0.04	1.17 ± 0.11	5.9
H144A	57 ± 8	0.69 ± 0.04	0.20 ± 0.02	1.0
D146A	>400	>2	∼0.08d	<0.4

^a Apo-MshB was incubated with stoichiometric Zn²⁺ for 30 min prior to activity measurement.

^b Substrate used GlcNAc.

^c Data adapted from Ref. 14.

^d Estimated from slope of initial linear region on V versus [S] plot.