Related Experiment Video
Updated: Oct 12, 2026

Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
Characterization of hydrogen peroxide and superoxide degrading pathways of Aspergillus niger catalase: a steady-state
1Unité de Chimie des Interfaces, Université Catholique de Louvain, Belgium.
Abstract:
The oxidized intermediates generated upon exposure of Aspergillus niger catalase to hydrogen peroxide and superoxide radical fluxes were examined with UV-visible spectrophotometry. Hydrogen peroxide and superoxide radical were generated by means of glucose/glucose oxidase and xanthine/xanthine oxidase systems. Serial overlay of absorption spectra in the Soret (350-450 nm) and visible regions (450-700 nm) showed that the decomposition of hydrogen peroxide by the catalase of Aspergillus niger can proceed through one of two distinct pathways: (i), the normal "catalatic" cycle consisting of ferric catalase-->Compound I-->ferric catalase; (ii), a longer cycle where superoxide radical transforms Compound I to Compound II which is then converted to the resting ferric enzyme via Compound III. The latter sequence of reactions ensures that the catalase of Aspergillus niger restores entirely its activity upon exposure to low levels of superoxide radicals due to the actions of oxidases.
More Related Videos
Related Concept Videos
Catalysis
Autoxidation of Ethers to Peroxides and Hydroperoxides
Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate
Electron Transport Chain: Complex III and IV
Reaction Mechanisms: The Steady-State Approximation
Catalysis
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
