RESUMEN
Nitrite reductases (NiRs) are the key enzymes in the denitrification pathway of the nitrogen cycle. By the catalysis of NiRs, the nitrites are turned into nitric oxides and the nitrogen pollution is decreased in water body. NiRs are divided into two different types based on their prosthetic groups, namely heme-containing nitrite reductases (cd1-NiRs) and Copper-containing nitrite reductases (Cu-NiRs). As all know, Cu-NiRs have trimeric structures, in their each monomer, there exist two types of Cu centers that play pivotal roles as the components of electron transfer pathway in the process of catalysis. Furthermore, some residues alteration of Cu-NiRs would contribute to the catalytic reaction. In this review, the latest progresses about the construction features, the process of electron transfer and catalytic mechanism of Cu-NiRs were discussed.