The Mechanism of Nitrite Reductase.

ABSTRACT: Cytochrome c nitrite reductase (CcNiR) activates nitrite and produces ammonia. It is one of several enzymes that use a redox-active cofactor to perform its reaction. In this case, the cofactor has a heme with a lysine as the proximal ligand and a charged nearby arginine. The role of a tyrosine, which is also close, has been less clear. There are also four bis-histidine-ligated hemes involved in the electron transfers. CcNiR has been studied before, using essentially the same methods as here. However, the mechanism is very complicated, involving six reductions, and quite different results for the mechanism have been obtained here. For example, the tyrosine has here been found to be redox active in the final step when ammonia is produced. Also, the arginine has here been found to stay proton

SUBMITTER: Siegbahn PEM 

PROVIDER: S-EPMC11932435 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature