Table 2.

Kinetic properties of TDPX1 and TryP1 with TryX as reducing agent with different hydroperoxides

peroxide substrate	k₁ (ROOH) [M^-1 s^-1] × 10⁵	k₂ (TryX) [M^-1 s^-1] × 10⁶	k _cat [s⁻¹]	K_m (ROOH) [μM]	K_m (TryX ) [μM]
TDPX1
hydrogen peroxide^a	0.80 ± 0.18	6.9 ± 1.5	15.4 ± 1.4	193 ± 27	2.2 ± 0.3
hydrogen peroxide^b	1.0 ± 0.06	6.2 ± 0.6	21.4 ± 7.4	211 ± 74	3.5 ± 1.2
t-butyl hydroperoxide^a	0.068 ± 0.0019	5.2 ± 1.6	15.2 ± 2.0	2244 ± 353	2.9 ± 0.5
cumene hydroperoxide^a	0.79 ± 0.09	6.2 ± 0.7	16.2 ± 0.7	207 ± 14	2.6 ± 0.2
TryP1
hydrogen peroxide^b	13 ± 2	1.7 ± 0.1	8.8 ± 1.0	6.3 ± 0.8	4.9 ± 0.6
t-butyl hydroperoxide^b	8.9 ± 0.8	1.8 ± 0.1	7.8 ± 0.8	10.5 ± 1.4	4.3 ± 0.5
cumene hydroperoxide^b	11 ± 1.5	3.0 ± 0.2	8.6 ± 0.5	8.0 ± 0.7	2.8 ± 0.2

^a)

The initial velocities of 30 individual assays with different TryX and hydroperoxide concentrations were globally fitted to the equation describing a ping-pong mechanism (see “experimental procedures”). Values are the means and standard errors obtained by non-linear regression.

^b)

The data were calculated using the integrated Dalziel rate equation (see “experimental procedures”). Values are the weighted means and standard deviations of two independent experiments obtained by linear regression.