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 D is a normal lysosomal protease that is expressed in all cells. It is an aspartyl protease with a pH optimum in the range of 3-5, and contains two N-linked oligosaccharides. Cathepsin D is synthesized as an inactive 52kD pro-enzyme. Activation involves the proteolytic removal of the 43 amino acid profragment and an internal cleavage to generate the two-chain form made up of 34 and 14kD subunits.
Cathepsin D contains the mannose-6-phosphate lysosomal localization signal that targets the enzyme to the lysosomal compartment where it functions in the normal degradation of proteins. In certain tumor cells, Cathepsin D is abnormally processed and is secreted in its 52kD precursor form. Numerous clinical studies as well as in vitro evidence suggest that cathepsin D plays an important role in malignant transformation and may be a useful prognostic indicator for breast cancer.
Specific Activity:~300u/mg
Unit Definition:1 unit is the amount of enzyme that digests hemoglobin-releasing peptides which are soluble in 10% TCA. The reaction is measured by an increase of an A280 of 1.0 per 60 minutes at 37°C. Substrate: Acid denatured hemoglobin (0.2% in reaction mixture). Buffer: 0.1M formate, pH 3.3.
Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile ddH2O. Aliquot to avoid repeated freezing and thawing. Store 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.
仕様
Size:25ug
Source Antigen:Human liver
Grade:Highly Purified
Purity:~95% (SDS-PAGE)
Form:Supplied as a lyophilized powder from 2mM sodium phosphate, pH 6.5. Reconstitute with ~200ul sterile ddH2O.