This family is comprised of a group of predicted cysteine proteases, homologous to the Ovarian Tumour (OTU) gene in Drosophila. Members include proteins from eukaryotes, viruses and pathogenic bacterium. The conserved cysteine and histidine, and possibly the aspartate, represent the catalytic residues in this putative group of proteases.

1: A novel superfamily of predicted cysteine proteases from eukaryotes, viruses and Chlamydia pneumoniae. Makarova KS, Aravind L, Koonin EV; Trends Biochem Sci 2000;25:50-52. PMID:10664582