Anti-Cathepsin B antibodies are used in the immunodetection of the protein encoded by the CTSB gene. In humans, the canonical protein has a reported length of 339 amino acid residues and a mass of 37.8 kDa. Its subcellular localization is in the lysosomes and cell membrane. It is reported to be expressed in the stratum spinosum of the epidermis. A member of the Peptidase C1 protein family, it is reported to be a thiol protease, which is believed to participate in intracellular degradation and turnover of proteins. Post-translational modifications have been described, including glycosylation. Other names for this target antigen include CPSB, KWE, RECEUP, APP secretase, amyloid precursor protein secretase, cathepsin B1, cysteine protease, and APPS.