- Primary structure from amino acid and cDNA sequences of two Cu,Zn superoxide dismutase variants from Xenopus laevis. Schininà, M.E., Barra, D., Bossa, F., Calabrese, L., Montesano, L., Carrì, M.T., Mariottini, P., Amaldi, F., Rotilio, G. Arch. Biochem. Biophys. (1989)