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Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases
Published on: February 24, 2018
Extracellular superoxide dismutase exists as an octamer
Anne V Due1, Steen V Petersen, Zuzana Valnickova
1Center for Insoluble Protein Structures (inSPIN), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
FEBS Letters
|February 14, 2006
Summary
Human extracellular superoxide dismutase (EC-SOD) forms an octamer, not just a tetramer, influencing its local concentration. This discovery offers new insights into protecting tissues from oxidative stress.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- Extracellular superoxide dismutase (EC-SOD) is crucial for defending against oxidative stress from superoxide radicals.
- The EC-SOD protein typically exists as a homotetramer, stabilized by N-terminal hydrophobic interactions.
Purpose of the Study:
- To investigate the quaternary structure of EC-SOD purified from human aorta.
- To explore the formation of higher-order EC-SOD structures and their stability.
Main Methods:
- Purification of EC-SOD from human aorta.
- Heparin-Sepharose chromatography to identify EC-SOD variants.
- Thermodynamic stability analysis of EC-SOD oligomers.
Main Results:
- A previously uncharacterized EC-SOD octamer was identified with high affinity for heparin-Sepharose.
- Thermodynamic analysis indicated the C-terminal region's involvement in octamer formation.
- The octamer comprises both aEC-SOD and iEC-SOD folding variants.
Conclusions:
- EC-SOD can form an octameric structure in addition to the known tetramer.
- The C-terminal region plays a role in the stabilization of the EC-SOD octamer.
- The EC-SOD octamer may regulate local enzyme concentration for targeted tissue protection against oxidative damage.
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