Cathepsin E

Cathepsin E is an intracellular aspartic protease of the pepsin family. Unlike Cathepsin D, another member of the same family and a lysosomal protease with relatively ubiquitous distribution, Cathepsin E is not a lysosomal enzyme and has a limited cell and tissue distribution. However, both Cathepsins D and E play an important role in the degradation of proteins, the generation of bioactive proteins, and antigen processing. Both enzymes are efficient in cleaving the Swedish mutant of amyloid precursor protein (APP) at the β site but show almost no reactivity with the wildtype APP. Mouse Cathepsin E is synthesized as a precursor protein, consisting of a signal peptide (residues 1-18), a propeptide (residues 19-59), and a mature chain (residues 60-397) .