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Updated: Jan 3, 2026

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Functional interactions between nitrite reductase and nitric oxide reductase from Paracoccus denitrificans
Ingrid Albertsson1, Johannes Sjöholm1,2, Josy Ter Beek1,3
1Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, SE-106 91, Stockholm, Sweden.
Interactions between nitric oxide-producing nitrite reductase (cd1NiR) and nitric oxide-reducing reductase (cNOR) were studied in P. denitrificans. Transient interactions were observed, influencing enzyme activity and dimerization, potentially protecting cells from toxic nitric oxide.
Area of Science:
- Microbiology
- Biochemistry
- Environmental Science
Background:
- Denitrification is a key microbial process in the nitrogen cycle.
- Nitric oxide (NO) is a toxic intermediate produced during denitrification.
- Understanding enzyme interactions is crucial for cellular protection and metabolic regulation.
Purpose of the Study:
- To investigate the functional interaction between cd1 nitrite reductase (cd1NiR) and c-type nitric oxide reductase (cNOR) in P. denitrificans.
- To determine if these enzymes interact to facilitate NO channeling and protect against toxicity.
- To elucidate the impact of these interactions on enzyme activity and oligomerization.
Main Methods:
- Enzymatic assays were performed to assess the interaction between purified cd1NiR and cNOR.
- Studies focused on electron donation to cNOR in the presence of cd1NiR.
- Analysis of cd1NiR dimerization in the presence of cNOR was conducted.
Main Results:
- Electron donation to cNOR was inhibited by the presence of cd1NiR, suggesting competitive binding.
- cNOR influenced the dimerization state of cd1NiR.
- No evidence of high-affinity, constant interaction was found, but transient interactions were supported.
Conclusions:
- Transient interactions between cd1NiR and cNOR occur in P. denitrificans.
- These interactions modulate the enzymatic activity of cNOR and the oligomerization of cd1NiR.
- Such interactions may be significant in vivo during metabolic transitions, particularly between aerobic and denitrifying conditions.
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