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Updated: Jul 3, 2026

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
The nitrite anion binds to human hemoglobin via the uncommon O-nitrito mode
Jun Yi1, Martin K Safo, George B Richter-Addo
1Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
Abstract:
The nitrite anion is known to oxidize and degrade hemoglobin (Hb). Recent literature reports suggest a nitrite reductase activity for Hb, converting nitrite into nitric oxide. Surprisingly, no structural information about Hb-nitrite interactions has been reported. We have determined the crystal structure of the ferric Hb-nitrite complex at 1.80 A resolution. The nitrite ligand adopts the uncommon O-nitrito binding mode. In addition, the nitrito conformations in the alpha and beta subunits are different, reflecting subtle effects of the distal His in orienting the nitrite ligand in the O-nitrito binding mode.
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