EC 184.108.40.206 - Cathepsin X
IntEnz Enzyme Nomenclature
lysosomal carboxypeptidase B
- Release of C-terminal amino acid residues with broad specificity, but lacks action on C-terminal proline. Shows weak endopeptidase activity.
Cathepsin X is a lysosomal cysteine peptidase of family C1 (papain family). The pH optimum is dependent on the substrate and is 5.0 for the carboxypeptidase activity. Unstable above pH 7.0. Compound E-64, leupeptin and antipain are inhibitors, but not cystatin C. Cathepsin X is ubiquitously distributed in mammalian tissues. The propeptide is extremely short (38 amino acid residues) and the proenzyme is catalytically active. Human gene locus: 20q13.
Links to other databases
Human cathepsin X: A cysteine protease with unique carboxypeptidase activity.Biochemistry 38: 12648-12654 (1999). [PMID: 10504234]
Human cathepsin X: A novel cysteine protease of the papain family with a very short proregion and unique insertions.FEBS Lett. 434: 135-139 (1998). [PMID: 9738465]
Cathepsin Z, a novel human cysteine proteinase with a short propeptide domain and a unique chromosomal location.J. Biol. Chem. 273: 16816-16823 (1998). [PMID: 9642240]
On the substrate specificity of cathepsins B1 and B2 including a new fluorogenic substrate for cathepsin B1.Life Sci. 17: 1269-1276 (1975). [PMID: 577]
Improved purification of cathepsin B1 and cathepsin B2.Biochim. Biophys. Acta 379: 462-475 (1975). [PMID: 1122298]
Purification and characterization of rat liver lysosomal cathepsin B2.Biochim. Biophys. Acta 370: 308-321 (1974). [PMID: 4429705]
[EC 220.127.116.11 created 1981, modified 2000]