. Author manuscript; available in PMC: 2009 Jan 1.

Published in final edited form as: J Biol Inorg Chem. 2008 Oct 2;14(1):133–142. doi: 10.1007/s00775-008-0431-2

Table 1.

The rate constants (s^-1) of the FMN–heme IET reaction (k^obs _et) and CO rebinding process (k_CO) obtained for the iNOS holoenzymes ^a

	580 nm trace		465 nm trace		430 nm trace		455 nm trace
	k^obs_et	k_CO	k^obs_et	k_CO	k^obs_et	k_CO	k_CO
Murine iNOS ^b	35 ± 3	1.1 ± 0.3	36 ± 2	0.9 ± 0.4	35 ± 2	0.8 ± 0.4	1.8 ± 0.1
Human iNOS ^c	35 ± 5	0.9 ± 0.1	32 ± 3	0.8 ± 0.1	29 ± 2	0.7 ± 0.1	3.6 ± 0.6 (53%)
							0.7 ± 0.2 (47%)

Buffer: 40 mM bis-Tris propane, 400 mM NaCl, 2 mM l-Arg, 20 μM H₄B, 1 mM Ca²⁺ and 10% glycerol, pH 7.6. 20 μM dRF solutions with 5 mM fresh semicarbazide in the buffer were used. A mixture of CO/Ar (1:3) was used to degas the dRF solution and purge the concentrated iNOS. k^obs _et values for murine and human iNOS oxyFMN constructs are 850 ± 50 s^-1 [19] and 320 ± 45 s^-1 (this study), respectively.

Experiments were repeated with 4.6 and 7.4 μM murine iNOS.

Experiments were repeated twice at 11 μM human iNOS.