Figure 5.

The assay of the total cellular superoxide dismutases (SODs) (A) and catalases (CATs) (B) activities in the E. magnusii yeast. A—The activity of SODs in cell suspension was assessed by monitoring of A₄₀₆ with a spectrophotometer upon inhibition of quercetin autooxidation. The procedure was performed in 20 mM KP_i buffer, pH 10.2; containing 0.8 mM TMDA, 0.1 mM EDTA, and 1.4 µM quercetin. 50% inhibition of quercetin autoxidation was considered as a SODs enzymatic activity unit. Values are mean ± SEM from 5–6 independent experiments. B—Total CATs activity was assessed by monitoring the cellular homogenate at 240 nm with a Specol-11 spectrophotometer (Germany). The procedure was performed in 20 mM KPi buffer, pH 7.2, containing 2 mM EDTA. The reaction was triggered by the application of H₂O₂ (the molar extinction coefficient 46.3 M⁻¹ cm⁻¹). The CATs activity was measured by monitoring the decrease in hydrogen peroxide concentration. A₂₄₀ was determined every 15 s for 3 min after the reaction start. Catalase activity was expressed in µmol-used H₂O₂ × min⁻¹× mg⁻¹ of protein. Error bars represent the standard deviation of triplicates to each experiment. a, b—p < 0.05, c—did not differ significantly.