. Author manuscript; available in PMC: 2016 Jul 1.

Published in final edited form as: J Biol Inorg Chem. 2015 May 7;20(5):805–819. doi: 10.1007/s00775-015-1267-1

Table 4.

Rate constants obtained from reduction of oxidized WT*/K73H by hexaammineruthenium(II) chloride at 25 °C in 10 mM buffer, 0.1 M NaCl.^a

pH	k_ET (mM⁻¹, s⁻¹)^b	k_b,His (s⁻¹)^c	k_f,His (s⁻¹)^d
5	44 ± 2	9 ± 2	-
6	47 ± 1	8.8 ± 0.7	-
7	42.4 ± 0.5	9.2 ± 0.4	2 ± 3
8	34.6 ± 0.7	8.76 ± 0.08	2.8 ± 0.7
9	31.6 ± 0.2	9.9 ± 0.2	7 ± 1

Errors are standard errors reported by SigmaPlot unless otherwise noted

k_ET is obtained from fits to Eq. 5, as described in the text. The intercepts, k_uni, of the fits to Eq. 5 were close to zero within error

At pH 5 and 6, k_b,His73 is taken as the average value of k_gET,2 across all concentrations of a₆Ru²⁺. Error is the standard deviation of the average. At pH 7 to 9, k_b,His is from fits to Eq. 6, as described in the text

From fits to Eq. 6, as described in the text