The Schizosaccharomyces pombe sdu⁺ gene encoding a putative member of the PPPDE (Permuted Papain fold Peptidases of DsRNA viruses and Eukaryotes) superfamily was cloned into an Escherichia coli - yeast shuttle vector pRS316, resulting in the recombinant plasmid pYSTP. The determined nucleotide sequence carries 1207 bp, which would encode a protein of 201 amino acid residues. The S. pombe cells harboring pYSTP contained higher sdu1⁺ mRNA and deubiquitinating activity levels than the vector control cells, indicating that the sdu1⁺ gene is functioning. They exhibited a better growth in normal rich medium than the vector control cells. When shifted into the fresh medium containing hydrogen peroxide, menadione, or sodium nitroprusside, the S. pombe cells harboring pYSTP were able to grow reasonably well, while the growth of the vector control cells was arrested. The reactive oxygen species and total glutathione levels of the S. pombe cells harboring pYSTP were lower and higher than those of the vector control cells under the same stressful conditions, respectively. They exhibited a lower nitric oxide level than the vector control cells when subjected to sodium nitroprusside. Taken together, the sdu1⁺ gene encodes an actual protein having deubiquitinating activity and is involved in the response against oxidative and nitrosative stresses in S. pombe.