Purification and Characterization of Superoxide Dismutases from Sea Buckthorn and Chestnut Rose

Superoxide dismutases (SODs) were purified from sea buckthorn and chestnut rose by ammonium sulfate precipitation and anion-exchange chromatography, and the detection methods of water-soluble tetrazolium-1 (WST-1), nitrobluetetrazolium (NBT) and pyrogallol autoxidation (PA) for SOD activity were compared. WST-1 method was selected due to its coefficient of variation (CV) <6% in this study. Two SODs exhibited similar characteristics. Their molecular mass and isoelectric point were about 30 kDa and 4.8 to 5.0 estimated by electrophoresis, and the K_m was 0.05 to 0.08 mmol/L, respectively. Dynamic light scattering analysis suggested their hydrodynamic radius distributes from 60 to 1500 nm. The activity of two SODs was unchanged at <80 °C or pH 2 to 9 or in simulated human gastric fluid. Their circular dichroism spectra suggested a main β-sheet structure, the fluorescence spectra reflected that the tryptophan residues of two SODs is partially exposed, these structures were rather stable at pH 2 to 9 or 50 to 90 °C. PRACTICAL APPLICATION: Superoxide dismutase (SOD) is an important antioxidant enzyme. SODs from sea buckthorn and chestnut rose were stable at high temperature or low pH or simulated gastric fluid. This result can provide a new approach for the potential application of SOD in the food and pharmaceutical fields.