CTSZ Human

Cathepsin-Z has a very short pro-region that shows no similarity to those of other cathepsins. It also contains a three-residue insertion motif that forms a characteristic ‘mini loop’. Unlike other cathepsins, Cathepsin-Z does not act as an endopeptidase but exhibits mono- and di-peptidase activity at its C-terminus .

Cathepsin-Z is widely expressed in human tissues, suggesting its involvement in normal intracellular protein degradation across various cell types. It is predominantly found in cells of the immune system, such as monocytes, macrophages, and dendritic cells . This enzyme is capable of cleaving regulatory motifs at the C-terminus, affecting the function of targeted molecules. It may also play a role in the maturation of dendritic cells, which is crucial for the initiation of adaptive immunity .

Higher levels of Cathepsin-Z are observed in tumor and immune cells of prostate and gastric carcinomas, as well as in macrophages of the gastric mucosa, especially after infection by Helicobacter pylori. This enzyme is also ubiquitously distributed in cancer cell lines and primary tumors from different sources, suggesting its potential involvement in tumor progression .

Recombinant Human Cathepsin-Z is typically produced in HEK293 cells and is available with a His tag for purification purposes. The recombinant protein is often lyophilized from sterile PBS, pH 7.4, and may contain protectants such as trehalose, mannitol, and Tween80 .

Lyophilized recombinant Cathepsin-Z proteins are generally stable for up to 12 months when stored at -20 to -80°C. Once reconstituted, the protein solution can be stored at 4-8°C for 2-7 days, and aliquots can be stored at < -20°C for up to 3 months .