Recombinant Mouse Cathepsin L Protein, CF

Cathepsin L is a lysosomal cysteine protease expressed in most eukaryotic cells. Cathepsin L is known to hydrolyze a number of proteins, including the proform of urokinase‑type plasminogen activator, which is activated by Cathepsin L cleavage (1). Cathepsin L has also been shown to proteolytically inactivate alpha ₁-antitrypsin and secretory leucoprotease inhibitor, two major protease inhibitors of the respiratory tract (2). These observations, combined with the demonstration of increased Cathepsin L activity in the epithelial lining fluid of the lungs of emphysema patients, have led to the suggestion that the enzyme may be involved in the progression of this disease. Cathepsin L has also been identified as a major excreted protein of transformed fibroblasts, indicating the enzyme could be involved in malignant tumor growth (3). In Cathepsin L‑deficient mice, it appears to play a critical role in cardiac morphology and function, epidermal homeostasis, regulation of the hair cycle, and MHC class II‑mediated antigen presentation in cortical epithelial cells of the thymus (4, 5). Mouse Cathepsin L is synthesized as a 334 amino acid precursor with a signal peptide (residues 1‑17), a pro region (residues 18‑113) and a mature chain (residues 114‑334).