Nitric oxide complexes nonheme iron proteins

Pellat, C., Henry, Y., and Drapier, j. C. (1990). IFN-gamma-activated macrophages Detection by electron paramagnetic resonance of complexes between L-arginine-derived nitric oxide and nonheme iron proteins. Biochem. Biophys. Res. Commun. 166, 119-125. 

VI. NITRIC OXIDE COMPLEXES OF OTHER NONHEME IRON PROTEINS... 

But, because there was also a first-order term, reduction via a dinitrosyl complex may not be compulsory. It is doubtful that cytochromes could participate in NO reduction via dinitrosyl complexes, because of strong axial coordination of Fe by at least one protein ligand. It is of course possible that the nonheme iron of nitric oxide reductase is the actual site of reduction of NO. 

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