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 L, a lysosomal endopeptidase, is a member of the papain-like family of cysteine proteinases. It is involved in the promotion of tumor cell invasion, antigen processing and turnover of intracellular and secreted proteins. The SensoLyte®Rh110 Cathepsin L Activity Assay Kit provides a convenient assay for screening Cathepsin L inhibitors or assay of enzyme activity using a fluorogenic substrate. Upon cleavage by Cathepsin L, this substrate generates the Rh110 (rhodamine 110) fluorophore with a bright green fluorescence that can be detected at excitation/emission=490/520 nm. The longer wavelength spectra and higher extinction coefficient of Rh110 provide greater sensitivity and less interference from other reaction components.Kit size: 100 assays (96-well plate)