Anti-CTSK Antibody

Cathepsin K is a lysosomal cysteine protease expressed predominantly by osteoclasts, where it degrades type I collagen during bone resorption. This unconjugated rabbit polyclonal reagent from Antibodies.com is raised against the CTSK protein and supplied as a 200 µl liquid aliquot, validated for Western blot and immunohistochemistry workflows. Because the polyclonal response recognizes multiple epitopes across the mature protease and its precursor, the reagent can be used to probe denatured lysates for the cleaved active chain as well as the full-length zymogen, and to stain fixed osteoclasts and chondrocytes in tissue sections.

Reactivity against mouse, rat, and duck samples makes this antibody a useful tool for cross-species comparative skeletal biology, including rodent models of osteoporosis, ovariectomy-induced bone loss, rheumatoid bone erosion, and avian studies of beak and long-bone development. The reagent is provided in a phosphate-buffered formulation and should be aliquoted and stored at -20 °C, with short-term bench use kept at 4 °C and repeated freeze-thaw cycles avoided. Researchers can pair immunostaining with orthogonal methods such as TRAP activity assays or qPCR for cathepsin K transcripts to confirm expression patterns in osteoclast-rich tissues and tumor microenvironments where cathepsin activity contributes to invasion.