nitrite reductase (NO-forming) activity

Definition

Target type: molecularfunction

Catalysis of the reaction: nitric oxide + H2O + ferricytochrome c = nitrite + ferrocytochrome c + 2 H+. [EC:1.7.2.1, MetaCyc:NITRITE-REDUCTASE-CYTOCHROME-RXN]

Nitrite reductase (NO-forming) activity catalyzes the reduction of nitrite (NO2-) to nitric oxide (NO), a crucial step in the nitric oxide cycle. This enzyme is commonly found in bacteria and fungi, where it plays a vital role in nitrogen metabolism and detoxification. The enzymatic mechanism involves the transfer of electrons from a reducing agent, often a reduced cytochrome c or ferredoxin, to nitrite, ultimately leading to the release of NO. The enzyme utilizes a variety of metal cofactors, typically heme or copper, which are essential for the electron transfer process.

The NO produced by nitrite reductase has a wide range of biological functions, including:

* **Signaling:** NO acts as a signaling molecule in various physiological processes, such as vasodilation, neurotransmission, and immune response.
* **Antimicrobial activity:** In some organisms, NO serves as an antimicrobial agent, inhibiting the growth of pathogens.
* **Nitrogen fixation:** In certain bacteria, NO can be further reduced to ammonia (NH3), which is essential for nitrogen fixation.

The regulation of nitrite reductase activity is tightly controlled to ensure proper NO production and prevent detrimental effects. Factors influencing its activity include the availability of nitrite, the redox state of the electron donor, and the presence of specific inhibitors.

Overall, nitrite reductase (NO-forming) activity is a critical enzyme in the nitric oxide cycle, contributing to diverse biological processes through the production of NO. Understanding its molecular function is essential for unraveling the complex roles of NO in various organisms.'
"

Proteins (2)

Compounds (10)