Cathepsin L is a type of enzyme known as a cysteine protease, which plays a crucial role in breaking down proteins within cells. It is primarily found in lysosomes, the cell's recycling centers, where it helps digest cellular waste and recycle proteins for new cellular functions. This enzyme is important for various biological processes, including tissue remodeling, immune response, and cell signaling. Abnormal levels of Cathepsin L have been linked to several diseases, such as cancer and neurodegenerative disorders, making it a target for potential therapeutic interventions.