Table 2. Kinetic parameters of MmCobD and truncated MmCobD^1-385 for ATP.

SeCobD, MmCobD, MmCobD^1-385, and MmCobD^386-497 enzymes were assayed for ATPase activity. using a NADH consumption assay (see Materials and Methods). Enzymes were purified and assayed oxically or anoxically as indicated. These parameters are apparent kinetic values of the mean ± standard deviation of triplicate independent experiments. For steady-state analysis, the L-Thr concentration was saturating at 10 mM and ATP was gradually increased. ND, not detected.

A. Cooperativity
			ATPa,b,c
Protein	Assay condition	R2	Vmax (μM s−1)	K0.5 (mM)	kcat (s−1)	kcat/K0.5 (M−1 s−1)	h
MmCobD1−385	oxic	0.97	0.06 ± 0.003	72 ± 5	0.02 ± 0.001	0.27 ± 0.24	3 ± 0.4
MmCobD	oxic	0.91	0.08 ± 0.004	48 ± 2	0.03 ± 0.001	0.54 ± 0.53	5 ± 1.0
SeCobD	anoxic	-	ND	ND	ND	-	-
B.Michaelis-Menten
			ATP
Protein	Assay condition	R2	Vmax (μM s−1)	Km (mM)	kcat (s−1)	kcat/Km (M−1 s−1)
MmCobD	anoxic	0.97	0.08 ± 0.002	0.05 ± 0.006	0.04 ± 0.0001	720 ±150
MmCobD386−497	anoxic	-	ND	ND	ND	-

^aThese parameters are apparent kinetic values of averages of triplicate independent experiments and standard deviations.

^bFor steady-state analysis, the L-Thr concentration was saturating at 10 mM

^cND, not detected