procathepsins

Procathepsins are the inactive precursor forms of cathepsins, which are a group of cysteine proteases. These enzymes play crucial roles in various cellular processes, including protein degradation, antigen presentation, and bone resorption. The procathepsin molecule contains an activation peptide that must be cleaved to generate the active cathepsin enzyme. This cleavage typically occurs in the acidic environment of the lysosome, the cellular organelle where cathepsins are primarily found. Procathepsins themselves have limited enzymatic activity, serving as a mechanism to prevent premature or uncontrolled protease activity within the cell. The maturation process involves a series of proteolytic cleavages, often initiated by other proteases, leading to the formation of the mature, active enzyme. Dysregulation of procathepsin processing and activation has been implicated in a range of diseases, including cancer, inflammatory disorders, and neurodegenerative conditions, highlighting their importance in cellular homeostasis and disease pathogenesis.