Technical Data
C2097-03
Cathepsin B
Description:
Cathepsins are localized primarily in lysosomes or endosomes, but translocated to the cytosol during apoptosis. The translocation allows these proteases to interact with caspases or other apoptosis signaling mechanisms. Studies show that cathepsins cleave certain caspases, and caspase inhibitors can inhibit cathepsin activity in vitro. Cathepsin B is a normal lysosomal proteinase that is expressed in all cells. It is a cysteine endoproteinase structurally and functionally related to the papain family of proteases. Cathepsin B is synthesized as an inactive 43kD pro-enzyme which, by removal of a 62 amino acid propeptide, is activated to the single-chain form of 31kD or the two-chain form (25 and 5kD subunits). Matured cathepsin B is normally localized in the lysosomes where it functions in protein turnover. Cathepsin B is also shown to be capable of degrading extracellular matrix proteins at acidic and neutral pH. Endogenous inhibitors of cysteine proteases, the cystatins and stefins, may play a major role in regulating their activity. In tumor cells and in cells exposed to mitogens, cathepsin B displays altered cellular trafficking resulting in the secretion of the 43kD precursor. Elevated levels of cathepsin B correlate with malignancy suggesting that this enzyme may be a useful prognostic marker for several types of human cancers.

Applications:
Suitable for use in Western Blot and Immunohistochemistry. Other applications have not been tested.

Recommended Dilution:
Western Blot: 0.5-4ug/ml
Immunohistochemistry: 10-20ug/ml
Optimal dilutions to be determined by the researcher.

Storage and Stability:
May be stored at 4°C for short-term only. For long-term storage, store at -20°C. Aliquots are stable for at least 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
TypeIsotypeCloneGrade
PabIgGAffinity Purified
SizeStorageShippingSourceHost
100ug4°C (-20°C Glycerol)Blue IceHumanRabbit
Concentration:
~0.2mg/ml
Immunogen:
Synthetic peptide surrounding aa322 of human cathepsins B.
Purity:
Purified by immunoaffinity chromatography.
Form
Supplied as a liquid in PBS, pH 7.2, 0.1% thimerosal, 0.5% BSA, 30% glycerol.
Specificity:
Recognizes both the pro- (37-43kD) and mature (25kD) forms of human cathepsin B. Species Crossreactivity: mouse, rat (weak).
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.
1. Barrett, A.J. and Kirschke, H., Methods Enzymol. 80: 535-561 (1981). 2. Chan, S.J., et al. PNAS 83: 7721-7725 (1986).