title: Nitrite reduction: a ubiquitous function from a pre-aerobic past.
abstract: In eukaryotes, small amounts of nitrite confer cytoprotection against ischemia/reperfusion-related tissue damage in vivo, possibly via reduction to nitric oxide (NO) and inhibition of mitochondrial function. Several hemeproteins are involved in this protective mechanism, starting with deoxyhemoglobin, which is capable of reducing nitrite. In facultative aerobic bacteria, such as Pseudomonas aeruginosa, nitrite is reduced to NO by specialized heme-containing enzymes called cd(1) nitrite reductases. The details of their catalytic mechanism are summarized below, together with a hypothesis on the biological role of the unusual d(1)-heme, which, in the reduced state, shows unique properties (very high affinity for nitrite and exceptionally fast dissociation of NO). Our results support the idea that the nitrite-based reactions of contemporary eukaryotes are a vestige of earlier bacterial biochemical pathways. The evidence that nitrite reductase activities of enzymes with different cellular roles and biochemical features still exist today highlights the importance of nitrite in cellular homeostasis.
authors: Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza-Università di Roma, Rome, Italy. francesca.cutruzzola@uniroma1.it
authors: Francesca
authors: F
authors: Cutruzzolà
authors: Serena
authors: S
authors: Rinaldo
authors: Nicoletta
authors: N
authors: Castiglione
authors: Giorgio
authors: G
authors: Giardina
authors: Israel
authors: I
authors: Pecht
authors: Maurizio
authors: M
authors: Brunori
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000378:metabolism; D005057:Eukaryotic Cells / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D009573:Nitrites; D009569:Nitric Oxide