Disease relevance of CTSO

• The cathepsin O cDNA was expressed in Escherichia coli, and after purification and refolding, the recombinant protein was able to degrade the synthetic peptides benzyloxycarbonyl-Phe-Arg-7-amido-4- methylcoumarin and benzyloxycarbonyl-Arg-Arg-7-amido-4-methylcoumarin widely used as substrates for cysteine proteinases [1].

High impact information on CTSO

• Cathepsin O proteolytic activity was abolished by trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), an inhibitor of this subclass of proteolytic enzymes, thus providing additional evidence that the isolated cDNA codes for an authentic cysteine proteinase [1].
• Chromosomal localization of CTSO revealed that it maps to chromosome 4q31-q32, which is a unique location for all cysteine proteinases mapped to date [2].
• The gene (HGMW-approved symbol CTSO) is composed of eight coding exons and seven introns and spans more than 30 kb [2].
• Based on its high homology to OC2, we have named the human enzyme cathepsin O. Cathepsin O mRNA was identified as a single approximately 1.7 kb transcript in cultures of 15-day-old monocyte-derived macrophages, but was not expressed in human monocytes or alveolar macrophages [3].
• When transfected into COS-7 cells, cathepsin O displayed potent endoprotease activity against fibrinogen at acid pH [3].

Associations of CTSO with chemical compounds

• A newly synthesized artificial vitamin B6 derivative, a pridoxal propionate derivative, CLIK-164, showed selective inhibition of cathepsin O/K [4].

Analytical, diagnostic and therapeutic context of CTSO

• Human cathepsin O. Molecular cloning from a breast carcinoma, production of the active enzyme in Escherichia coli, and expression analysis in human tissues [1].
• Northern blot analysis of poly(A)+ RNAs isolated from a variety of human tissues demonstrated that cathepsin O is expressed in all examined tissues, which is consistent with a putative role of this protein as a proteolytic enzyme involved in normal cellular protein degradation and turnover [1].

References