Cathepsin S Activity Fluorometric Assay Kit

Apoptosis is often mediated by the traditional caspase-mediated cleavage cascade. In addition, alternative proteolytic enzymes such as the lysosomal cathepsin proteases can also initiate or propagate proapoptotic signals. Cathepsins are lysosomal proteases that play an important role in mammalian cellular turnover such as bone resorption. Cathepsins are often used as sensitive markers in a variety of toxicological investigations. Cathepsin S is a lysosomal cysteine protease belonging to the peptidase C1 family and is involved in the degradation of antigenic proteins to peptides for presentation on MHC class II molecules. Cathepsin S also plays an important role in itch and pain, or nociception.

 The Cathepsin S Activity Fluorometric Assay Kit provides a sensitive, simple and convenient way for detection of cathepsin S activity based on fluorometric method. The assay utilizes the preferred cathepsin-S substrate sequence VVR labeled with AFC (amino-4-trifluoromethyl coumarin). While cleavage of the synthetic substrate Z-VVR-AFC by cathepsin-S in cell lysates or other samples, free AFC emits a yellow-green fluorescence (λmax = 505 nm) that can be easily quantified using a fluorecence microtiter plate reader or a fluorometer.