The concentration of extracellular superoxide dismutase in plasma is maintained by LRP-mediated endocytosis
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Updated: Jun 11, 2026

Use of Electron Paramagnetic Resonance in Biological Samples at Ambient Temperature and 77 K
Published on: January 11, 2019
Steen V Petersen1, Ida B Thøgersen, Zuzana Valnickova
1Department of Molecular Biology, Center for Insoluble Protein Structures and Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark.
Abstract:
In this study, we show that human extracellular superoxide dismutase (EC-SOD) binds to low-density lipoprotein receptor-related protein (LRP). This interaction is most likely responsible for the removal of EC-SOD from the blood circulation via LRP expressed in liver tissue. The receptor recognition site was located within the extracellular matrix-binding region of EC-SOD. This region encompasses the naturally occurring Arg213Gly amino acid substitution, which affects the affinity of EC-SOD for ligands in the extracellular space. Interestingly, the binding between LRP and Arg213Gly EC-SOD was significantly reduced, thus clarifying the observation that hetero- or homozygous carriers present with a significant increase in EC-SOD in their blood. On the basis of our results, we speculate that EC-SOD synthesized locally in tissues diffuses slowly into the circulation, from where it is removed by binding to LRP present in the liver. The interaction between LRP and EC-SOD is thus likely to be important for maintaining redox balance in the circulation.
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