Table 2.

EPR and UV-visible absorbance spectroscopic parameters of nitrosyl complexes formed in nonheme iron enzymes catalyzing thiol oxidation^e

Protein	Protein ligand	Substrate coordination	Enzyme-nitrosyl complex	ES-nitrosyl complex
ADOa	3-His	Monodentate, via thiol	{Fe(NO)}7, S = 3/2, g = 4.10, 3.95, 2.00; 340, 406 nm	{Fe(NO)2}9, S = 1/2, g = 2.04, 2.01; 390 or 397 nm
CDOb	3-His	Bidentate, via thiol and amine	{Fe(NO)}7, S = 3/2, g ∼ 4, 4, 2	{Fe(NO)}7, S = 1/2, g = 2.07, 2.02, 1.98
3MDOc	3-His	Unclear, thiol involved	Not applicable	{Fe(NO)}7, S = 3/2, g = 4.06, 3.96, 2.00
IPNSd	2-His-2-carboxylate	Monodentate, via thiol	{Fe(NO)}7, S = 3/2, g = 4.09, 3.95, 2.00; 340, 430, 600 nm	{Fe(NO)}7, S = 3/2, g = 4.22, 3.81, 1.99; 508, 720 nm

^a Results from this work.

^b Results from references 28 and 47.

^c Results from references 8 and 52.

^d Results from references 39 and 62.

^e For EPR parameters, only the enzyme-based, predominant species are summarized here.