Description_x000D_ General description_x000D_ Cathepsin K belongs to the peptidase C1 protein family and is a lysosomal cysteine protease. The associated gene is strongly expressed on osteoclasts and is also present in cardiomyocytes. Cathepsin K is the most abundant and main protease involved with osteoclastic activity._x000D_ Biochem/physiol Actions_x000D_ Cathepsin K is responsible for collagenolytic and elastolytic activities. It can degrade type II collagen and thus participates in the degradation of articular cartilage. It also plays an important role in osteoarthritis and periodontitis. Removal of the cathepsin K activity provides protection against agents inducing metabolic stress in the heart. Absence of cathepsin K also protects from age-related decline in cardiac function by inhibition of caspase-associated and caspase-independent cell death._x000D_ Physical form_x000D_ 0.5 mg/mL solution in 25 mM Na2HPO4 and 500 mM NaCl (pH 7.0) with 50% glycerol.