SOD1 and amyotrophic lateral sclerosis: The ALS-linked SOD1 mutants have been grouped into two general classes, “wild-type-like mutants” resulting from mutations in the beta barrel or dimer interface, which generally retain high levels of catalytic activity, and metal-binding region mutants, resulting mostly from mutations in the loops, which generally have much less catalytic activity and are isolated with lower metal content than WT SOD1 [3].