The cathepsin family comprises several proteolytic enzymes stored in cellular organelles called lysosomes. A key cellular pathway involving lysosomes is Autophagy, the process of cellular self-digestion, where cathepsins hydrolyze and degrade cytoplasmic proteins, bulk cytoplasm, and dysfunctional organelles for recycling.
Cathepsins also play a role in phagocytosis and upon release from lysosomes into the cytoplasm, cathepsins can initiate or regulate apoptosis through both the extrinsic and intrinsic pathways by different mechanisms.
Increased levels of cathepsin activity have been linked with diseases such as cancer, arthritis and Alzheimer’s, indicating that cathepsin proteins may be a potential target for novel therapies.
We have the following range of cathepsin kits available supported by detailed technical manuals which you can download:
NOTE: All these kits may also be used with fluorescence plate readers.
Our Magic Red cathepsin detection kits allow analysis of active cathepsins in whole, living cells. Their methodology utilizes a substrate-based assay with a cresyl violet fluorophore probe. The cresyl violet is non fluorescent when it is bound through amide links to two target peptides. Active cathepsins can cleave the target peptide at an amide link which causes the mono cresyl violet fluorophore to emit red fluorescence (>610nm) when excited at 540-590 nm. Uncleaved target peptides have excitation and emission wavelengths of 592 nm and 628 nm, respectively, resulting in minimal cellular auto-fluorescence.
The photostable substrates for cathepsin B: (z-Arginine-Arginine)2, cathepsin K: (z-Leucine-Arginine)2 and cathepsin L: (z-Phenylalanine-Arginine)2 easily cross the plasma membrane and intracellular organelle membranes of living cells. Cathepsin activity can be determined by the accumulation of red fluorescent cresyl violet fluorophore substrate hydrolysis within organelles. An increase in cathepsin activity results in a greater fluorescent signal. Cellular analysis may be performed with a fluorescence microscope or plate reader.
Our kits also contain Hoechst stain for labeling nuclei and acridine orange for lysosome and organelle identification.
View the other sections in our quality apoptosis antibodies and kits product range:
Cresyl violet is synthesized by Enzyme Systems Products
Magic Red™ is a trademark of Immunochemistry Technologies, LLC.