Cysteine proteinase type I (CPB) (CPB)

Cysteine proteinase type I (CPB) is a key lysosomal enzyme in Leishmania parasites, belonging to the papain-like C1 family of cysteine proteases (UniProt: P25775). It is predominantly expressed during the amastigote stage of the parasite's life cycle, where it functions within the acidic environment of the host macrophage's phagolysosome (PubMed: 11566129). CPB is essential for the degradation of host and parasite proteins, facilitating nutrient acquisition and the evasion of host immune responses by degrading MHC class II molecules and other immune factors (PubMed: 15608515). Because of its central role in parasite survival and pathogenesis, CPB is a highly validated therapeutic target for various forms of leishmaniasis (PubMed: 22403315). Small molecule inhibitors, such as K777 and various peptidomimetics, have demonstrated potent anti-leishmanial activity by blocking the enzyme's active site (PubChem: CID 16124688). A major challenge in developing CPB-targeted therapies is ensuring high selectivity to avoid inhibiting human cathepsins, which could lead to adverse side effects (PubMed: 18463027).

Other names

Cysteine proteinase BCathepsin L-like cysteine proteinaseCysteine protease type ICPB1CPB2

Inhibition of the catalytic cysteine residue within the enzyme's active site, preventing the degradation of essential proteins and disrupting parasite metabolism and host-cell modulation (PubMed: 22403315).