Metal binding and an intramolecular disulfide bond stabilize the hSOD1 homodimer structure in the WT and ALS mutants, while loss of the intramolecular disulfide and formation of aberrant intermolecular disulfide aggregates the protein (Arnesano et al. 2004; Furukawa et al. 2006). This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.