Cathepsins are a class of globular lysosomal proteases, playing a vital role in mammalian cellular turnover. They degrade polypeptides and are distinguished by their substrate specificities. Cathepsin D is the lysosomal aspartic proteinase, active in intracellular protein breakdown. It is involved in the pathogenesis of several diseases such as breast cancer and Alzheimer disease. The SensoLyte® 390 Cathepsin D Activity Assay Kit uses a Mca/Dnp FRET peptide for measurement of enzyme activity. In the FRET peptide, the fluorescence of Mca is quenched by Dnp. Upon cleavage into two separate fragments by Cathepsin D, the fluorescence of Mca is recovered, and can be monitored at excitation/emission = 330 nm/390 nm.
Component A: Mca/Dnp, Cathepsin D substrate, Ex/Em=330/390 nm upon cleavage: 1.6 mM, 50 µL
Component B: Mca fluorescence reference standard, Ex/Em=330/390 nm: 2 mM, 10 µL
Component C: Cathepsin D, bovine spleen: 0.1 mg/mL, 20 µL
Component D: Assay Buffer: 20 mL
Component E: Pepstatin A: 4 mM, 100 µL
Component F: DTT: 1 M, 100 µL
Storage & stability
Store all kit components at -20°C, except for Component C. Store Component C at -80°C. Protect Components A and B from light and moisture. Component D can be stored at room temperature for convenience.