Table 2. Stop-flow kinetic data for the ODNB reaction with tubulin.

ODNB (1.0 mM) in syringe A and 4 μM tubulin (80 μM SH) in syringe B were mixed in the ratio 1:1 at the onset of the reaction; data were collected at a scan rate of 1/16 ms (scan range 395–545 nm). Data at 412 nm were extracted and fitted to a three-exponential equation using Olis-analysis software. k₁, k₂ and k₃ are first-order rate constants and A₁, A₂ and A₃ are the corresponding amplitudes. The kinetics was measured at 25 °C and at two pH values: pH 6.9 (Mes a.b.) and pH 8.5 (0.1 M Tris/HCl).

PH	k1 (s−1)	A1	k2 (s−1)	A2	k3 (s−1)	A3
6.9	0.010±0.002	0.022±0.002	0.069±0.004	0.091±0.004	0.206±0.01	0.068±0.005
8.5	0.096±0.01	0.040±0.006	0.332±0.02	0.084±0.006	4.29±0.4	0.062±0.004