Hematian S, Siegler MA, Karlin KD. Heme/copper assembly mediated nitrite and nitric oxide interconversion.
J Am Chem Soc 2012;
134:18912-5. [PMID:
23130610 DOI:
10.1021/ja3083818]
[Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The heme(a3)/Cu(B) active site of cytochrome c oxidase is responsible for cellular nitrite reduction to nitric oxide; the same center can return NO to the nitrite pool via oxidative chemistry. Here, we show that a partially reduced heme/Cu assembly reduces NO(2)(-) ion, producing nitric oxide. The heme serves as the reductant, but the Cu(II) ion is also required. In turn, a μ-oxo heme-Fe(III)-O-Cu(II) complex facilitates NO oxidation to nitrite; the final products are the reduced heme and Cu(II)-nitrito complexes.
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