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 43aa 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.
Applications:
Suitable for use in Western Blot and Immunohistochemistry. Other applications not tested.
Recommended Dilution:
Western Blot: 2.5-5ug/ml
Immunohistochemistry (Formalin fixed paraffin embedded): 5ug/ml
Optimal dilutions to be determined by the researcher.
Storage and Stability:
May be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.