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Cathepsin B from human liver

buffered aqueous solution, ≥1,500 units/mg protein (E1%/280)

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Cathepsin B1
CAS Number:
Enzyme Commission number:
MDL number:

biological source

human liver

Quality Level


buffered aqueous solution

specific activity

≥1,500 units/mg protein (E1%/280)

UniProt accession no.

shipped in

dry ice

storage temp.


Gene Information

human ... CTSB(1508)

General description

Cathepsin B gene is mapped to human chromosome 8p23.1. It is a lysosomal cysteine with 252 amino acids distributed in two chains and is homologous to rat liver sequence. It has disc shaped structure with two domains namely the left-hand ′L′ domain at the amino terminal and right hand ′R′ domain at the carboxyl-terminal.


Cathepsin B from human liver has been used:
  • as a positive control in the screening Cathepsin B inhibitor assay
  • in wall extension (expansin activity) assay
  • in microinjection human foreskin fibroblasts to test its effect on apoptosis induction

Biochem/physiol Actions

Cathepsin B from human liver is highly expressed in the esophageal adenocarcinoma (EAC). It reduces hepatic inflammation and fibrogenesis and may serve as a potential candidate for treating liver diseases.
Cathepsin B has been found to cleave procaspase 1 and procaspase 11 and to induce apoptosis in digitonin-permeabilized cells. Translocation of cathepsin B from the cytoplasm to the nucleus contributes to bile salt induced apoptosis of rat hepatocytes. Levels of cathepsin B in PC12 cells significantly decrease 12 to 24 hours after apoptosis is induced.


Package size based on protein content

Unit Definition

One unit will liberate 1 nanomole of 7-amino-4-methylcoumarin from Z-Arg-Arg 7-amido-4-methylcoumarin per min at pH 6.0 at 40 °C.

Physical form

Solution in 50 mM sodium acetate, pH 5.0, with 1 mM EDTA.

Storage Class Code

10 - Combustible liquids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

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Cathepsin B is a lysosomal cysteine proteinase with broad specificity. This protocol uses Nα–CBZ–Arg–Arg–7–amido–4–methylcoumarin as the substrate for fluorometric detection of Cathepsin B activity.

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