Related Experiment Video
Updated: Jul 18, 2026
![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)
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Mechanisms of electron transfer in catalysis by copper zinc superoxide dismutase
Valeriy V Smirnov1, Justine P Roth
1Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
Abstract:
Activated oxygen intermediates during copper zinc superoxide dismutase (SOD) catalysis were investigated using an isotope fractionation technique and natural abundance reagents. Competitive oxygen kinetic isotope effects (KIEs) are reported for the enzyme-catalyzed disproportionation of superoxide as well as the stoichiometric reaction of reduced SOD with molecular oxygen. Analysis within the context of quantum mechanical electron transfer theory provides evidence against an outer-sphere mechanism for O2*- oxidation. A CuII-O2-I intermediate is, therefore, proposed. The SOD-catalyzed oxidation of O2*- is characterized by an inverse (<1) KIE which is similar to those determined for the analogous reactions of synthetic copper compounds. An inverse kinetic isotope effect upon the enzymatic reduction of O2*- is also observed and proposed to arise from rate-determining proton transfer which leads to the formation of HO2* in the SOD active site.
More Related Videos
09:12[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
Related Concept Videos
Introduction to Mechanisms of Enzyme Catalysis
Introduction to Mechanisms of Enzyme Catalysis
Electron Transport Chain: Complex III and IV
Heterogeneous Catalysis
Catalysis
Catalysis