Si. Liochev et I. Fridovich, Copper- and zinc-containing superoxide dismutase can act as a superoxide reductase and a superoxide oxidase, J BIOL CHEM, 275(49), 2000, pp. 38482-38485
The copper- and zinc-containing superoxide dismutase can catalyze the oxida
tion of ferrocyanide by O-2(.-) as well as the reduction of ferricyanide by
O-2(.-) Thus, it can act as a superoxide dismutase (SOD), a superoxide red
uctase (SOR), and a superoxide oxidase (SOO). The human manganese-containin
g SOD does not exert SOR or SOO activities with ferrocyanide or ferricyanid
e as the redox partners. It is possible that some biological reductants can
take the place of ferrocyanide and can also interact with human manganese-
containing superoxide dismutase, thus making the SOR activity a reality for
both SODs. The consequences of this possibility vis a vis H2O2 production,
the overproduction of SODs, and the role of copper- and zinc-containing su
peroxide dismutase mutations in causing familial amyotrophic lateral sclero
sis are discussed, as well as the likelihood that the biologically effectiv
e SOD mimics, as described to date, actually function as SORs.