TABLE 1.

Kinetic parameters for NR at 4 °C: comparison of steady-state, pre-steady-state, and simulation results

The values were obtained from the experimental data performed in 50 mm potassium phosphate, pH 7.50, at 4 °C under anaerobic conditions using stopped-flow spectrophotometer or kinetic simulations. The kinetic parameters (steady-state kinetics) are as follows: k_cat = 1.7 ± 0.3 s⁻¹, K_m^NADH = 35 ± 8 μm; K_m^PNBA = 130 ± 5 μm.

Kinetic parameters; pre-steady state		Extinction coefficients
From experiment	From simulation	Chemical species	From experiment	From simulation
		m−1 cm−1
	k1a = 1.3 × 107 m−1 s−1	Eox	14,300	14,340
	k-1a = 6250 s−1	Eox:NADH		10,200
k2 = 700 ± 20 s−1	k2 = 700 s−1	Ered:NAD+		1,940
k3 = 65 ± 3 s−1	k3 = 60 s−1	Ered	931	920
KdNADH = 0.51 ± 0.04 mm	KdNADH, k-1/k1 = 0.48 mm	Ered:PNBA		2,850
	k4a = 6.8 × 105 m−1 s−1	Eox:Nitroso		18,240
	k−4a = 181 s−1
k5 = 1.90 ± 0.09 s−1	k5 = 2 s−1
KdPNBA = 0.33 ± 0.04 mm	KdPNBA, k−4/k4 = 0.27 mm

^a The values provided are not necessarily unique but are able to fully explain the data observed in conjunction with the model we provide. The values of k₁ and k₋₁ are inversely correlated, as are the values of k₄ and k₋₄.