Human SOD1 Recombinant Protein. SOD1 (superoxide dismutase) binds copper and zinc ions and is one of two isozymes responsible for destroying free superoxide radicals in the body. This isozyme is a soluble cytoplasmic protein, acting as a homodimer to convert naturally-occuring but harmful superoxide radicals to molecular oxygen and hydrogen peroxide. The other isozyme is a mitochondrial protein. Mutations in this gene have been implicated as causes of familial amyotrophic lateral sclerosis. Rare transcript variants have been reported for this gene.