FIGURE 5.
Effect of superoxide dismutase on cytochrome c reduction by plant sulfite oxidase reaction as monitored spectrophotometrically. Representative transients for each reaction are shown. Solid line, reaction of 20 nm plant sulfite oxidase with 1 mm sulfite and 532 μm O2 in the presence of 20 μm cytochrome c. Dashed line, same reaction in the presence of 200 units/ml superoxide dismutase. Dotted line, initial slope of the first reaction, yielding a value of 31.5 μm/min. The experiment was performed in Tris acetate buffer, pH 8.0, at 4 °C.