TABLE 2.

Steady-state bisubstrate kinetic parameters of XfPrxQ

Substrate	Kinetic parameters of XfPrxQa
	Vmaxb	kcat	Kmc	kcat/Km
	μm s−1	s−1	μm	m−1s−1
Hydrogen peroxide	0.24 ± 0.02	1.10 ± 0.07	33 ± 19	3.35 × 104
XfTsnC			6.8 ± 1.3	1.62 × 105
TBHP	0.09 ± 0.04	0.41 ± 0.18	72 ± 41	0.56 × 104
XfTsnC			3.0 ± 1.9	1.34 × 105
CHP	0.44 ± 0.16	2.00 ± 0.73	37 ± 19	5.34 × 104
XfTsnC			12.2 ± 5.5	1.64 × 105

^a Steady-state bisubstrate kinetic analyses of XfPrxQ were performed as described in Fig. 5.

^b These values are the 1/(y intercept ± S.D.) of the replot of the y intercept of primary plot versus 1/hydroperoxide concentration in Fig. 5 (right plots).

^c For hydroperoxide substrates, these values are the average ± S.D. of K_m obtained from the nonlinear regression analysis of initial rate versus hydroperoxide concentration, using GraphPad Prism 4. For XfTsnC, these values were obtained from (slope ± S.D.) of the replot of the y intercept of the primary plot versus 1/(hydroperoxide concentration) in Fig. 5 (right plots) multiplied by the V_max obtained here (slope = K_m(XfTsnC)/V_max).