Table 2.

Mössbauer Parameters of Oxidized (o) and Reduced (r) Heme Sites 1 and 2 of TDO^a

state	spin	δ (mm/s)	ΔEQ (mm/s)	% amount
o1, o2	5/2	0.42	1.53, η = 0	100
r1, r2	2	1.0	3.3, 3.8	80(5)
r-minor	2	1.0	2.6	20(5)
r1-Trp	2	1.0	3.1, 3.6	35(5)
r2-Trp	2	0.95	2.54	65(5)b
ra-CO	0	0.29	0.37	50(10)
rb-CO	0	0.29	0.76	50(10)
o1red-OHc	0	0.55	1.70, η = 0	25(3)d
o2red	2	0.95	2.54	25(5)
o1red-anneal	2	1.00	3.31	20(3)d,e
o2red-anneal	2	0.95	2.54	25(5)

^aEach row grouping specifies the heme states in the same protein sample.

^bMay contain 20% minor species.

^cSuperscript “red” refers to the cryoreduction of the oxidized state.

^d50% of the iron remained ferric.

^e5% of the iron remained o1^red-OH.