Cathepsin O is a cysteine protease and a member of the cathepsin family and papain superfamily. This proteolytic enzyme is involved in cellular protein degradation and turnover. The recombinant form of this enzyme was shown to degrade synthetic peptides typically used as substrates for cysteine proteinases and its proteolytic activity was abolished by an inhibitor of cyteine proteinase.
↑Santamaría I, Pendás AM, Velasco G, López-Otín C (October 1998). "Genomic structure and chromosomal localization of the human cathepsin O gene (CTSO)". Genomics. 53 (2): 231–4. doi:10.1006/geno.1997.5180. PMID9790772.
Velasco G, Ferrando AA, Puente XS, et al. (1994). "Human cathepsin O. Molecular cloning from a breast carcinoma, production of the active enzyme in Escherichia coli, and expression analysis in human tissues". J. Biol. Chem. 269 (43): 27136–42. PMID7929457.