SODs catalyze the dismutation of two superoxide radicals into oxygen and hydrogen peroxide.
Catalase catalyzes the reduction of hydrogen peroxide into oxygen and water. SOD and catalase act in concert to prevent cellular damage by removing the superoxide and hydrogen peroxide generated during electron transport and other processes. In maize, the mitochondrial Mn-SOD, a tetrameric enzyme, is synthesized on cytosolic polyribosomes with a cleavable leader sequence of 31 amino acids at the amino terminus. The transit peptide is required to translocate the protein into maize mitochondria. Cotton fibers are single-celled, highly differentiated, epidermal cells of developing cotton ovules.