Heme proteins play vital roles in biological systems. In hypoxia conditions, a series of heme proteins, such as hemoglobin(Hb), myoglobin(Mb), cytochrome C(CytC), neuroglobin(Ngb) and cytoglobin(Cgb), exhibit nitrite reductase(NIR) activities, by catalyzing the reduction of NO-2 to NO, which is complementary to the pathway of NO generation via the oxidation of L-Arg in normoxia conditions. It showed that the protein conformation, the heme coordination state, intramolecular disulfide bond, and H-bond network may regulate the NIR activity, which was also affected by microenvironment, such as the...
