A Cu, Zn-superoxide dismutase gene ( sod1+) deletion mutant of fission yeast Schizosaccharomyces pombe was constructed and its properties were investigated. Superoxide dismutase activity was not detected in the mutant on activity staining of polyacrylamide gels. The mutant showed cysteine or methionine and lysine auxotrophy, slow growth and sensitivity to menadione. While expression of the apt1+ gene, induction of which depends on the Pap1 transcription factor, was induced at the same concentration of menadione in both the wild-type cell and the sod1 mutant, expression of the gpx1+ gene, induction of which depends on the Atf1 transcription factor, was induced at a lower concentration of menadione in the mutant compared with the wild-type control. Expression of the sod1+ gene was induced by oxidative stress and no induction was observed in pap1, prr1 and spc1 mutants.