. Author manuscript; available in PMC: 2010 Aug 4.

Published in final edited form as: Biochemistry. 2009 Aug 4;48(30):7150–7159. doi: 10.1021/bi900457x

Table 1.

Steady State Kinetics Parameters of WT and Mutants MshC from M.Smegmatis^a

Protein	k_cat, min^-1	K_m^-ATP, mM	K_m^-cys, mM	K_m^-GlcN-Ins, mM
WT	189 ± 11	1.8 ± 0.1	0.1 ± 0.01	0.16 ± 0.05
H55A	4.4 ± 0.5	5.2 ± 0.1	1.1 ± 0.2	0.01 ± 10^-3
W227F	1.0 ± 0.1	0.20 ± 0.05	0.4 ± 0.1	0.15 ± 0.06^b
W227H	1.9 ± 0.1	0.12 ± 0.01	0.12 ± 0.04	0.6 ± 0.01^b
T46V	1.8 ± 0.5	1.1 ± 0.03	1.9 ± 0.2	0.15 ± 0.08^b
T83V	29 ± 1	0.32 ± 0.06	0.02 ± 0.001	0.17 ± 0.05^b
D251N	0.45 ± 0.05	8.9 ± 1.6	0.48 ± 0.15	0.10 ± 0.06^b
D251A	0.16 ± 0.02	0.36 ± 0.011	0.17 ± 0.02	0.16 ± 0.01^b

Determined using spectrophotometric coupled enzyme assay to monitor the formation of AMP

Determined at fixed saturating concentrations of ATP and cysteine. Data were fit to eqs 1 and 2.