. Author manuscript; available in PMC: 2008 Dec 11.

Published in final edited form as: Biochemistry. 2007 Nov 13;46(49):14153–14161. doi: 10.1021/bi701151t

Table 1.

Catalytic Rates of MetSO Repair by Msr Enzymes

Enzyme	Substrate	V_max^a (μmol NADPH/mg min)	K_m^a (mM)	k_cat^b (s⁻¹)	k_cat/K_m^c (M⁻¹ s⁻¹)
MsrBA	MetSO	0.49 ± 0.03	1.7 ± 0.4	0.31 ± 0.02	180 ± 40
	CaM_ox	0.9 ± 0.2	0.12 ± 0.03^d	0.6 ± 0.1	5,000 ± 2,000
MsrA	MetSO	0.5 ± 0.1	2.0 ± 0.8	0.19 ± 0.04	100 ± 40
	CaM_ox	0.07 ± 0.02	0.07 ± 0.05^d	0.027 ± 0.007	400 ± 300
MsrB	MetSO	ND	ND	ND	ND
	CaM_ox	0.05 ± 0.01	0.05 ± 0.02^d	0.01 ± 0.01	200 ± 200

Data presented were obtained by fitting the experimental data to the Michaelis-Menten equation, $V = \frac{V_{max} [S]}{K_{m} + [S]}$ , where [S] is concentration of substrate, K_m is the Michaelis constant and V_max is the velocity when the reaction approaches a maximum. Reactions conditions are described in the legend of Figure 5.

k_cat = V_max × molecular weight = turnover number.

Errors were propagated.

Value are apparent and do not take into account the presence of multiple MetSO in oxidized CaM.