3.4.18.1	alpha-enolase + H2O	cathepsin X cleaves the C-terminal dipeptide of alpha- and gamma-enolase abolishing their neurotrophic activity	
3.4.18.1	bradykinin + H2O	the peptide is converted from a bradykinin B2 receptor ligand to a bradykinin B1 receptor specific ligand	
3.4.18.1	CXCL-12 + H2O	CXCL-12 is a physiological substrate for secreted cathepsin X	
3.4.18.1	gamma-enolase + H2O	cathepsin X cleaves the C-terminal dipeptide of alpha- and gamma-enolase abolishing their neurotrophic activity	
3.4.18.1	kallidin + H2O	the peptide is converted from a bradykinin B2 receptor ligand to a bradykinin B1 receptor specific ligand	
3.4.18.1	lymphocyte function associated antigen-1 + H2O	cathepsin X cleaves the beta2 cytoplasmic tail of LFA-1 inducing the intermediate affinity form of LFA-1 and alpha-actinin-1 binding. Cleavage by cathepsin X of the amino acid residues S769, E768 and A767 from the C-terminal of the b2 cytoplasmic tail of LFA-1 promotes binding of the actin-binding protein a-actinin-1	
3.4.18.1	additional information	active cathepsin X mediates the function of beta2 integrin receptors during cell adhesion. It could also be involved in other processes associated with beta2 integrin receptors such as phagocytosis and T cell activation	
3.4.18.1	additional information	cathepsin X plays a role not only in the chronic inflammation of gastric mucosa but also in the tumourigenesis of gastric cancer	
3.4.18.1	additional information	cathespin X is involved in phagocytosis and regulation of immune response, not involved in degradation of extracellular matrix, a proteolytic event leading to tumor cell invasion and metastasis	
3.4.18.1	additional information	cathepsin X binds to the membrane lectin endoplasmic reticulum Golgi intermediate compartment protein-53, ERGIC-53, involving the soluble luminal interaction partner multiple coagulation factor deficiency protein 2, MCFD2, which form a cargo receptor complex in the early secretory pathway, but is dispensable for enzyme binding, overview	
3.4.18.1	additional information	luminal protein-protein interactions between components of the cargo system in the endoplasmic reticulum for secretion of cargo proteins, e.g. cathepsin C or cathepsin Z, involve the cargo transport receptor ERGIC-53, i.e. endoplasmic reticulum-Golgi intermediate compartment protein of 53 kDa, with its luminal interaction partner MCFD2, i.e. multiple coagulation factor deficiency protein 2, MCFD2 is not required for the binding of cathepsin Z and cathepsin C to ERGIC-53 in vivo, overview	
3.4.18.1	additional information	procathepsin X supports integrin alphavbeta3-dependent attachment and spreading of umbilical vein endothelial cells, overvie	
3.4.18.1	additional information	the enzyme is associated with plaques in Alzheimer patients, overview	
3.4.18.1	additional information	the enzyme plays a role in immunity to pathogens including Mycobacterium tuberculosis, variation in the melanocortin 3 receptor and cathepsin Z genes play a role in the pathogenesis of tuberculosis in West African populations	
3.4.18.1	additional information	the enzyme stimulates macrophage antigen-1 receptor-dependent adhesion and phagocytosis via interaction with integrin beta2 subunit. It plays a role in regulating lymphocyte proliferation via Mac-1 and the other b2 integrin receptor, lymphocyte function-associated antigen-1. Cathepsin X has been shown to suppress proliferation of peripheral blood mononuclear cells, by activation of Mac-1, known as a suppressive factor for lymphocyte proliferation, co-localization of cathepsin X and LFA-1 enhances lymphocyte proliferation, overview	
3.4.18.1	additional information	CATX is an important player in the spinal mechanisms involved in chronic pain induction and maintenance	
3.4.18.1	additional information	CATX is widely expressed in the brain and is implicated in several neurological conditions such as Alzheimer's disease, amyotrophic lateral sclerosis and age-related inflammation	
3.4.18.1	additional information	cathepsin X acts as a monocarboxypepidase and has a strict positional and narrower substrate specificity relative to the other human cathepsins	
3.4.18.1	additional information	cathepsin X is an important regulator of LFA-1 activity, and cathepsin X-upregulated Jurkat T cells exhibit increased homotypic aggregation, cathepsin X induces polarized migration-associated morphology in Jurkat T cells, overview	
3.4.18.1	additional information	co-localization of alpha or gamma enolase and cathepsin X. Cathepsin X impairs survival and neuritogenesis of neuronal cells, e.g. it reduces PC12 cell survival and neuritogenesis	
3.4.18.1	profilin + H2O	cathepsin X cleaves profilin 1 C-terminal Tyr139 and influences clathrin-mediated endocytosis. Tyr139 is important for proper function of profilin 1 as a tumor suppressor. Cleaving off Tyr139 prevents the binding of clathrin, a poly-L-proline ligand involved in endocytosis	
3.4.18.1	profilin 1 + H2O	the molecular target of cathepsin X in tumor cells is profilin 1, a known tumor suppressor and regulator of actin cytoskeleton dynamics. Cathepsin X cleaves off the C-terminal Tyr139 of profilin 1, affecting binding of poly-L-proline ligands and, consequently, tumor cell migration and invasion. Tyr139 is important for proper function of profilin 1 as a tumor suppressor. Cleaving off Tyr139 prevents the binding of clathrin, a poly-L-proline ligand involved in endocytosis	
3.4.18.1	Proteins + H2O	-