Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cell membrane-bound proteolytic enzymes (ectopeptidases) are integral membrane proteins, orientated asymmetrically with the catalytic site exposed to the extracellular surface, which enables a versatile range of physiological and pathological functions. Ectopeptidases may regulate the release of many growth factors and their receptors into the circulation, as well as activating or inactivating circulating signalling molecules, thereby regulating the availability of ligands for the corresponding receptors. Additionally, many of these ectopeptidases have functions not limited to proteolysis, but are able in themselves to function as receptors, transducing intracellular signals. A versatile range of functions, such as the modulation of cell-signalling, matrix degradation, cell adhesion and migration, which are particularly important for tumour cell growth and dissemination, are attributed largely to the ectopeptidases. Even a minor disruption in the normal proteolytic equilibrium can influence tumor progression, and a range of ectopeptidases, including neutral endopeptidase 24.11, aminopeptidase N, dipeptidyl peptidase IV, angiotensin-converting enzyme, and the disintegrin-metalloproteinases, have been shown to be involved in tumour development and metastasis. The ability to degrade and inactivate peptide hormones and growth factors, with the resultant modulation of the tumour-host interface, may play an important role in the pathogenesis, development or progression of a range of cancers, and the extracellular orientation of the ectopeptidases makes them particularly accessible, and therefore interesting, with regard to therapeutical applications.
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PMID:Ectopeptidases in tumour biology: a review. 1697 85

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a 38- or 27-amino acid neuropeptide with promising therapeutic applications for the treatment of several pathophysiological states related to neurodegenerative diseases. However, its use for therapeutic applications is actually limited by its restricted bioavailability and rapid degradation. Therefore, metabolically stable PACAP analogs represent promising tools to further investigate the physiological roles of PACAP and ascertain its usefulness in some clinical conditions. In this study, derivatives of PACAP27 and PACAP38 have been rationally designed to develop PAC1 receptor agonists resistant to peptidase action. Results showed that N-terminal modifications confer resistance to dipeptidyl peptidase IV, a major proteolytic process involved in PACAP degradation. Moreover, in vitro incubation of both PACAP isoforms in human plasma revealed that PACAP38 is rapidly metabolized, with a half-life of less than 5 min, while PACAP27 was stable in these experimental conditions. Hence, following the elucidation of its plasmatic metabolites, PACAP38 was modified at its putative endopeptidase and carboxypeptidase sites of cleavage. All peptide analogs were tested for their ability to bind the PAC1 receptor, as well as for their potency to induce calcium mobilization and inhibit PC12 cell proliferation through the PAC1 receptor. This approach revealed two leading compounds, i.e. acetyl-[Ala15, Ala20]PACAP38-propylamide and acetyl-PACAP27-propylamide, which exhibited improved metabolic stability and potent biological activity. This study describes innovative data related to PACAP metabolism in human plasma and depicts the development of a metabolically stable PACAP38 analog, acetyl-[Ala15, Ala20]PACAP38-propylamide, which behaves as a super-agonist towards the PAC1 receptor.
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PMID:Novel stable PACAP analogs with potent activity towards the PAC1 receptor. 1835 7

Oxyntomodulin (Oxm) is an intestinal peptide that inhibits food intake and body weight in rodents and humans. These studies used peptide analogs to study aspects of structure and function of Oxm, and the sensitivity of parts of the Oxm sequence to degradation. Analogs of Oxm were synthesized and studied using receptor binding and degradation studies in vitro. Their effects on food intake and conditioned taste avoidance were measured in vivo in rodents. Oxm breakdown by the enzyme dipeptidyl peptidase IV (DPPIV) was demonstrated in vitro and in vivo. In vitro degradation was reduced and in vivo bioactivity increased by inhibitors of DPPIV. Modifications to the N terminus of Oxm modulated binding to the glucagon-like peptide (GLP)-1 receptor and degradation by DPPIV. Modifications to the midsection of Oxm modulated binding to the GLP-1 receptor and degradation by neutral endopeptidase. These modifications also altered bioactivity in vivo. The C-terminal octapeptide of Oxm was shown to contribute to the properties of Oxm in vitro and in vivo but was not alone sufficient for the effects of the peptide. Elongation and acylation of the C terminus of Oxm altered GLP-1 receptor binding and duration of action in vivo, which may be due to changes in peptide clearance. An Oxm analog was developed with enhanced pharmaceutical characteristics, with greater potency and longevity with respect to effects on food intake. These studies suggest that Oxm is a potential target for antiobesity drug design.
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PMID:Investigation of structure-activity relationships of Oxyntomodulin (Oxm) using Oxm analogs. 1907 79

Neuropeptidases play a key role in regulating neuropeptide signalling activity in the central nervous system of animals. They are oligopeptidases that are generally found on the surface of neuronal cells facing the synaptic and peri-synaptic space and therefore are ideally placed for the metabolic inactivation of neuropeptide transmitters/modulators. This review discusses the structure of insect neuropeptides in relation to their susceptibility to hydrolysis by peptidases and the need for specialist enzymes to degrade many neuropeptides. It focuses on five neuropeptidase families (neprilysin, dipeptidyl-peptidase IV, angiotensin-converting enzyme, aminopeptidase and dipeptidyl aminopeptidase III) that have been implicated in the metabolic inactivation of neuropeptides in the central nervous system of insects. Experimental evidence for the involvement of these peptidases in neuropeptide metabolism is reviewed and their properties are compared to similar neuropeptide inactivating peptidases of the mammalian brain. We also discuss how the sequencing of insect genomes has led to the molecular identification of candidate neuropeptidase genes.
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PMID:Neuropeptidases and the metabolic inactivation of insect neuropeptides. 1913 55

Circulating antiplasmin-cleaving enzyme (APCE), a prolyl-specific serine proteinase, is essentially identical to membrane-inserted fibroblast activation protein (FAP) that is transiently expressed during epithelial-derived cancer growth. Human precursive alpha(2)-antiplasmin (Met-alpha(2)AP), the only known physiologic substrate for APCE, is cleaved N-terminally to Asn-alpha(2)AP that is rapidly cross-linked to fibrin and protects it from digestion by plasmin. Identifying a specific inhibitor of APCE/FAP continues to be intensely pursued. Recombinant FAP cleavage of peptide libraries of short amino acid sequences surrounding the scissile bond, -Pro(12)-Asn(13)-, indicated that P2 Gly and P1 Pro are required, just as we found for APCE. We examined cleavage of P4-P4' peptides, using 19 amino acid substitutions at each position and selected ones in P8-P5. K(m) values determined for peptide substrates showed that P7 Arg has the highest affinity for APCE. Peptide cleavage rate increased with Arg in P6 rather than P5 or native P7. Placing Arg in P4 or P8 reduced cleavage rates dramatically. Cleavage of substrates with extended peptide sequences before or after the scissile bond showed endopeptidase to be superior to dipeptidase activity for APCE. A substrate analogue inhibitor, Phe-Arg-(8-amino-3,6-dioxaoctanoic acid)-Gly-[r]-fluoropyrrolidide, inhibited APCE with a K(i) of 54 microM but not dipeptidyl peptidase IV even at 2 mM. The inhibitor also blocked cleavage of Met-alpha(2)AP with an IC(50) of 91 microM. Replacing Arg with Gly at the same distance from fluoropyrrolidide as P7 Arg is from P1 Pro reduced its inhibition of APCE approximately 10-fold. Results indicate that Arg at P5, P6, or P7 distances from P1 enhances affinity and efficiency of substrates or inhibitors toward APCE or FAP.
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PMID:Using substrate specificity of antiplasmin-cleaving enzyme for fibroblast activation protein inhibitor design. 1940 13

Proteases constitute one of the primary targets in drug discovery. In the present review, we focus on extracellular proteases (ECPs) because of their differential expression in many pathophysiological processes, including cancer, cardiovascular conditions, and inflammatory, pulmonary, and periodontal diseases. Many new ECP inhibitors are currently under clinical investigation and a significant increase in new therapies based on protease inhibition can be expected in the coming years. In addition to directly blocking the activity of a targeted protease, one can take advantage of differential expression in disease states to selectively deliver therapeutic or imaging agents. Recent studies in targeted drug development for the metalloproteases (matrix metalloproteinases, adamalysins, pappalysins, neprilysin, angiotensin-converting enzyme, metallocarboxypeptidases, and glutamate carboxypeptidase II), serine proteases (elastase, coagulation factors, tissue/urokinase plasminogen activator system, kallikreins, tryptase, dipeptidyl peptidase IV) and cysteine proteases (cathepsin B) are discussed herein.
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PMID:Extracellular proteases as targets for drug development. 1968 54

The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP, gastric inhibitory peptide) are secreted from intestinal L and K cells and stimulate insulin secretion from pancreatic beta cells. However, they are immediately inactivated mainly via N-terminal degradation by dipeptidyl peptidase IV (DPP IV, CD26), a specialised enzyme located on the cell surface enzyme of endothelial, epithelial and some other cell types. Cleavage by neprilysin (neutral endopeptidase) is a minor degradation route, and renal clearance eliminates incretin/fragments, but appears of less importance for regulating incretin bioactivities. Based on these observations two novel types of drugs for the treatment of type 2 diabetes have been developed: DPP IV inhibitors and DPP IV-resistant incretin analogues. Both have distinct advantages and disadvantages. Potential side effects of DPP IV inhibitors may result from affecting the bioactivity of other hormones, neuropeptides or chemokines and also by their cross-reactivity with DPP IV-related enzymes.
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PMID:Mechanisms underlying the rapid degradation and elimination of the incretin hormones GLP-1 and GIP. 1974 62

Dipeptidyl peptidase (DP) 8 belongs to the dipeptidyl peptidase IV gene family. DP8 has been implicated in immune function and asthma, although its biological function is yet unknown. Structures of the homologs, fibroblast activation protein (FAP) and DPIV, are known but the DP8 structure is yet to be resolved. To help characterise the DP8 substrate pocket, mutants of residues lining the pocket were produced at DP8(D772), DP8(Y315), DP8(H434) and DP8(D435) and assessed by substrate kinetics and size-exclusion chromatography. Mutations of DP8(D772A/E/S/V) affected catalysis but did not confer endopeptidase activity. Mutations of DP8(H434F), DP8(D435F) and DP8(Y315F) reduced catalytic activity. Furthermore, mutations to DP8(D772A/E/S/V), DP8(H434F), DP8(D435F) and DP8(Y315F) affected dimer stabilisation. Homology modelling of DP8 using DPIV and FAP crystal structures suggested that DP8(D772), DP8(H434) and DP8(D435) were located at the edge of the S2 catalytic pocket, contributing to the junction between the alpha-beta hydrolase and beta-propeller domains. This study provides insights into how the DP8 substrate pocket and dimer interface differ from DPIV and FAP which could be utilised for designing more selective DP8 inhibitors.
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PMID:Hydrophilic residues surrounding the S1 and S2 pockets contribute to dimerisation and catalysis in human dipeptidyl peptidase 8 (DP8). 2053 96

Neutral endopeptidase (NEP/CD10) and dipeptidyl peptidase IV (DPP IV/CD26) are both ubiquitous glycopeptidases which play important roles in tumor pathogenesis and development. The aim of this study was to investigate the expression patterns and the prognostic significance of CD10 and CD26 in osteosarcoma patients. CD10 and CD26 expression in 116 pairs of primary osteosarcoma and corresponding noncancerous bone tissue samples from the same specimens were detected by immunohistochemistry. The Spearman's correlation was calculated between the expression levels of CD10 and CD26 in osteosarcoma tissues. The associations of CD10 and CD26 expression with the clinicopathologic features and with the prognosis of osteosarcoma were subsequently assessed. Both CD10 expression and CD26 expression in osteosarcoma tissues were significantly higher than those in corresponding noncancerous bone tissue samples (both P < 0.001). Overexpression of CD10 and CD26 were respectively observed in 68.10 % (79/116) and 70.69 % (82/116) of osteosarcoma tissues. A significant correlation was found between CD10 expression and CD26 expression in osteosarcoma tissues (r = 0.83, P < 0.001). In addition, combined overexpression of CD10 and CD26 was observed in 52.59 % (61/116) of osteosarcoma tissues. CD10-high/CD26-high expression was significantly correlated with advanced clinical stage (P = 0.001), positive metastatic status (P = 0.001), shorter overall (P < 0.001) and disease-free (P < 0.001) survival in patients with osteosarcomas. Furthermore, multivariate survival analysis showed that clinical stage, metastatic status, CD10 expression, CD26 expression and combined expression of CD10/CD26 were all independent prognostic factors for predicting both overall and disease-free survival of osteosarcoma patients. Interestingly, combined expression of CD10/CD26 had a better prognostic value than other features. This retrospective study offer the convincing evidence for the first time that the overexpression of CD10 or CD26 may be an important feature of human osteosarcomas, and the combined expression of CD10/CD26 may be an efficient prognostic indicator for this disease.
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PMID:Synergistic relationship between dipeptidyl peptidase IV and neutral endopeptidase expression and the combined prognostic significance in osteosarcoma patients. 2368 1

Fibroblast activation protein (FAP) is a cell-surface serine protease which promotes invasiveness of certain epithelial cancers and is therefore a potential target for cancer drug development and delivery. Unlike dipeptidyl peptidase IV (DPPIV), FAP exhibits prolyl endopeptidase activity and is active as a homodimer with specificity for type I collagen. The mechanism that regulates FAP homodimerization and its relation to prolyl endopeptidase activity is not completely understood. Here, we investigate key residues in the FAP TM domain that may be significant for FAP homodimerization. Mutations to predicted TM interfacial residues (G10L, S14L, and A18L) comprising a small-X3-small motif reduced FAP TM-CYTO dimerization relative to wild type as measured using the AraTM assay, whereas predicted off-interface residues showed no significant change from wild type. The results implied that the predicted small-X3-small dimer interface affect stabilization of FAP TM-CYTO homodimerization. Compared with FAPwild-type, the interfacial TM residue G10L significantly decreased FAP endopeptidase activity more than 25%, and also reduced cell-surface versus intracellular expression relative to other interfacial residues S14L and A18L. Thus, our results suggest FAP dimerization is important for both trafficking and protease activity, and is dependent on a specific TM interface.
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PMID:A specific, transmembrane interface regulates fibroblast activation protein (FAP) homodimerization, trafficking and exopeptidase activity. 2715 68


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