PARK7 belongs to the peptidase C56 family of proteins. It acts as a positive regulator of androgen receptor-dependent transcription. It may also function as a redox-sensitive chaperone, as a sensor for oxidative stress, and it apparently protects neurons against oxidative stress and cell death.

Northern blot analysis revealed that DJ1 is ubiquitously expressed as a 1.0-kb transcript. Western blot analysis and immunofluorescence showed that the DJ1 protein is present in both nuclei and cytoplasm of HeLa cells.A search of the GenBank protein database revealed that DJ1 has approximately 40% identity to the 198-amino acid protein product of the E. coli thiazole monophosphate biosynthesis (ThiJ) gene. A homolog also exists in the nematode C. elegans.