Cathepsin B, Human Liver

Research area: Cell Signaling

Native cathepsin B from human liver, purified by affinity chromatography and HPLC. The most investigated enzyme of all lysosomal cysteine proteases. Cathepsin B belongs to the papain-like family of cysteine proteases and is produced as a preproenzyme. It is a bilobal protein, and its catalytic site is situated at the interface between the two lobes.

Cathepsin B, Human Liver, has been used in:

• Diagnostics: as a potent and independent prognostic marker for endometrial cancer, pancreatic adenocarcinoma, and inflammatory disease.
• Drug development: during the neovascularization process and as a potent therapeutic target for various pathologies, cancer progression, and osteoarthritis in humans.
• Pharmacology: for increasing the therapeutic index of doxorubicin by incorporating the cathepsin B cleavable spacer Phe-Lys-4-aminobenzyloxycarbonyl into an albumin-binding prodrug.
• Molecular biology: in cathepsin B activity assay.

Cathepsin B acts as both endo and exopeptidase. While as an endopeptidase it cleaves amino acids with a large hydrophobic side chain in the P2 site of the protein/peptide substrate, on the other hand as an exopeptidase it eliminates two amino acids (dipeptide) from the C terminus of a polypeptide substrate, thereby categorizing the enzyme as a peptidyl dipeptidase. It maintains homeostatic metabolic activity within cells through regular turnover of both intracellular and extracellular proteins. Additionally, it is involved in various cellular functions like regulation of pro-enzyme and pro-hormone activation, tissue remodeling, antigen processing, apoptosis, and inflammatory responses to antigens. The expression and activity of cathepsin B have been linked to several pathologies, including cardiovascular disease, cancer, Alzheimer’s, arthritis, and pancreatitis. Overexpression of cathepsin B has been observed in brain, breast, gastric, prostate, esophageal, skin, lung, ovarian, colon, and thyroid cancers and correlates positively with their invasive and metastatic capabilities. Cathepsin B is shown to facilitate tumor invasion by dissolving extracellular barriers.

In 50 mM sodium acetate buffer, 1 mM EDTA, pH 5.0.

Following initial thaw, aliquot and freeze (-70°C).

Prepared from tissues of individuals that have been shown by certified tests to be negative for HBsAg and for antibodies to HIV and HCV.

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Berquim, I.M., and Sloane, B.F. 1996. Adv. Exp. Med. Biol.389, 281.

One unit is defined as the amount of enzyme that will hydrolyze 1.0 µmol Z-RR-β-naphthylamide per min at 40°C, using 100 mM Na⁺/K⁺ pH 6.0, with 1.33 mM EDTA and 2 mM DTT as the activation buffer.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)