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Percoll reversibly inhibits superoxide dismutase
Revista Espanola De Fisiologia
|September 1, 1985
Summary
Percoll solutions inhibit pea leaf superoxide dismutase (SOD) activity in a dose- and time-dependent manner, particularly Mn-SOD. This inhibition is reversible upon sample dilution, suggesting Percoll adsorption.
Area of Science:
- Plant biochemistry
- Enzyme kinetics
- Protein-ligand interactions
Background:
- Superoxide dismutase (SOD) is a crucial enzyme in antioxidant defense systems.
- Understanding factors affecting SOD activity is vital for plant stress response studies.
- Percoll is commonly used for density gradient centrifugation of plant organelles.
Purpose of the Study:
- To investigate the effect of Percoll on pea leaf superoxide dismutase (SOD) activity.
- To determine the specificity of Percoll's inhibitory action on different SOD isozymes.
- To elucidate the mechanism behind Percoll-induced SOD inhibition.
Main Methods:
- Incubation of pea leaf extracts with varying Percoll concentrations at 6°C.
- Assay of total SOD activity and analysis of isozyme profiles using electrophoresis.
- Investigation of Percoll's inhibitory effect reversibility through sample dilution.
Main Results:
- Percoll significantly repressed total SOD activity in a concentration- and time-dependent manner.
- Mn-SOD activity was inhibited by over 50% at 30-45% Percoll after 24h.
- Cu,Zn-SOD II showed moderate inhibition (up to 36%), while Cu,Zn-SOD I was minimally affected.
- Percoll's inhibitory effect was completely reversed by sample dilution prior to electrophoresis.
Conclusions:
- Percoll exhibits a concentration- and time-dependent inhibitory effect on pea leaf SOD activity.
- The inhibition mechanism likely involves reversible adsorption of SOD enzymes onto the Percoll surface via electrostatic interactions.
- These findings are important for researchers using Percoll in plant enzyme studies to avoid artifactual results.