Related Experiment Video
Updated: Aug 16, 2026

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Hunting oxygen complexes of nitric oxide synthase at low temperature and high pressure
Stéphane Marchal1, Antonius C F Gorren, K Kristoffer Andersson
1INSERM U710, Place Eugène Bataillon, Université Montpellier II, Montpellier, France.
Abstract:
The reaction of nitric oxide synthase (NOS) with oxygen is fast and takes place within several steps, separated by ephemeral intermediates. The use of extreme experimental conditions, such as low temperature and high pressure, associated to rapid kinetic analysis, has proven to be a convenient tool to study this complex reaction. Stopped-flow experiments under high pressure indicated that oxygen binding occurred in more than one step. This was further corroborated by the detection of two short-lived oxy-compounds, differing in their spectral and electronic properties. Oxy-I resembles the ferrous oxygen complex known for cytochrome P450, whereas oxy-II appears to be locked in the superoxide form. Subzero temperature spectroscopy, together with an analytical separation method, revealed that the subsequent one-electron reduction of the oxygen complex is carried out by the NOS cofactor tetrahydrobiopterin (BH4). The low-temperature stabilized oxidation product of BH4 was found to be a protonated BH3 radical. Finally, work in the presence of a BH4 analog indicated that proton transfer to the activated oxygen complex is a second essential function of BH4.
Related Concept Videos
Nitric Oxide Signaling Pathway
2° Amines to N-Nitrosamines: Reaction with NaNO2
Nitrosation of Enols
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Preparation of Nitriles

