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

Post-proline dipeptidyl aminopeptidase (dipeptidylpeptide hydrolase, EC 3.4.14.1), also known as glycylprolyl beta-naphthylamidase or dipeptidyl aminopeptidase IV, was isolated and purified in an overall yield of 20% from autolyzed extracts of lamb kidney by CM-cellulose and column chromatography on DEAE-Sephadex and Sephadex G-200. Purified enzyme was homogeneous by disc gel electrophoresis and ultracentrifugal analysis and was most active at pH 7.8 using Gly-Pro beta-napthylamide as substrate. The Km values for Gly-Pro beta-naphthylamide and Ala-Ala beta-naphthylamide were 0.63 and 0.77 mM, respectively. The proline-containing peptides were hydrolysed more than 10-fold faster. By isoelectric focusing a pI of 4.9 was determined. The enzyme was estimated to be 230 000 +/- 15 000 by the sedimentation equilibrium method and sodium dodecyl sulfate polyacrylamide gel electrophoresis indicating that the enzyme is composed of two identical subunits with molecular weights of 115 000. It was inhibited by the active-site directed, irreversible inhibitor diisopropylphosphorofluorofluoridate. Post-proline dipeptidyl aminopeptidase, in contrast to the endopeptidase post-proline cleaving enzyme [9,10] (Walter R. (1976) Biochim. Biophys. Acta 422, 138-158, and Koida, M. and Walter, R. (1976) J. Biol. Chem. 251, 7593-7599) exhibits no endopeptidase activity. Instead it is an exopeptidase with a high specificity for NH2-terminal-free peptides containing a proline residue in the penultimate position and releases the dipeptide with proline being the COOH-terminal moiety. The name "post-proline dipeptidyl aminopeptidase" is suggested.
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PMID:Post-proline dipeptidyl aminopeptidase (dipeptidyl aminopeptidase IV) from lamb kidney. Purification and some enzymatic properties. 92 19

1. Growing rats were fed either ad lib. or with six (equal) meals offered every 4 h (from 10.00 hours). Rats of each group were killed at intervals of 4 h beginning at 11.00 hours. Activities of cathepsin A (carboxypeptidase A; EC 3.4.12.2), C (dipeptidyl peptidase; EC 3.4.14.1) and D (endopeptidase D EC 3.4.23.5) were measured in liver and muscle homogenates and free amino acids in blood were determined. 2. In the rats fed ad lib. activities of carboxypeptidase A and endopeptidase D in liver and muscle showed significant variation, with maximum activity in the light period. In general, meal-feeding only caused minor differences in cathepsin activities; although significant differences occurred for carboxypeptidase A. For the later enzyme a peak in activity occurred in the dark as well as in the light period. 3. Irrespective of the feeding schedule, the lower concentration of free essential amino acids of blood occurred generally during the night period. With the controlled-feeding schedule there is an increase of essential amino acids and a slight decrease of non-essentail amino acids of blood.
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PMID:Variations through the day of hepatic and muscular cathepsin A (carboxypeptidase A; EC 3.4.12.2), C (dipeptidyl peptidase; EC 3.4.14.1) and D (endopeptidase D; EC 3.4.23.5) activities and free amino acids of blood in rats: influence of feeding schedule. 719 24

By employing various synthetic substrates, as well as soluble denatured protein substrate (TAP-lysozyme) and its derivatives, endopeptidase activity of cathepsin C, dipeptidyl aminopeptidase I [EC 3.4.14.1], from bovine spleen was investigated. Cathepsin C efficiently degraded Z-Phe-Arg-MCA, Pro-Phe-Arg-MCA, and Suc-Leu-Leu-Val-Tyr-MCA. This endopeptidase activity required sulfhydryl reagents and halide ions, as in the case of the dipeptidyl aminopeptidase (DAP) activity. We confirmed that this endopeptidase activity is due to cathepsin C itself based on the results on gel-filtration and anion-exchange chromatographies, comparative studies of the inhibitory effects of leupeptin and E-64 on this activity and those of cathepsins B and L, and further the competitive inhibitions by mutual substrates for the DAP and endopeptidase activities of cathepsin C. We also found that cathepsin C endopeptidase activity towards TAP-lysozyme and its N-alpha-acetylated tryptic peptides showed marked dependence on sulfhydryl reagents and chloride ion. Thus, we concluded that cathepsin C has endopeptidase activity as well as DAP activity. The binding energy between the enzyme and the amino acid side chains of the substrate may be as important for the endopeptidase activity as is the electrostatic interaction between the enzyme and the free alpha-amino group of the substrate for the DAP activity.
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PMID:Endopeptidase activity of cathepsin C, dipeptidyl aminopeptidase I, from bovine spleen. 851 33

Two kinds of dipeptidyl aminopeptidase I (DAP I [cathepsin C])-like activities which hydrolyze Gly-Phe-p-nitroanilide (Gly-Phe-pNA) were detected in Pseudomonas sp. strain WO24. They were purified and characterized. The isolated enzymes, named DAP BII and DAP BIII, were revealed to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing. DAP BII was estimated to have a molecular mass of 150,000 Da by gel filtration and a subunit size of 73,000 Da by SDS-PAGE, indicating it to be a homodimer. The molecular mass of DAP BIII was evaluated to be approximately 60,000 Da by gel filtration and 69,000 Da by SDS-PAGE, indicating that it is monomeric. The isoelectric points of DAP BII and DAP BIII were 6.1 and 5.0, and their optimal pHs were 8.0 and 8.5 to 9.0, respectively. The result of peptide mapping for DAP BII and DAP BIII showed that these enzymes consist of different components. Both enzymes were completely inhibited by diisopropylphosphofluoride but not by general thiol inhibitors, indicating that they are serine proteases. DAP BII and DAP BIII hydrolyzed Gly-Phe-pNA but not Gly-Arg-pNA, both of which are model substrates for mammalian DAP I. Despite these shared activities toward DAP I, DAP BII released dipeptides from Ala-Ala-pNA and Lys-Ala-4-methylcoumarinamide (a substrate for DAP II), whereas DAP BIII did not hydrolyze either of these compounds and was presumed to prefer substrates composed of bulky, hydrophobic amino acids at P1 and P1' positions. In addition, DAP BII showed no endopeptidase activity, whereas DAP BIII possessed the activity on N-terminally blocked peptide derivatives besides exopeptidase activity. Assays performed with bioactive peptides such as angiotensin I and neuromedin N as substrates indicate that DAP BII has a considerably broader substrate specificity than DAP BIII and is able to hydrolyze an X-Pro bond, an imido bond that few peptidases and no known DAPs can cleave. These characteristics, namely, substrate specificities, molecular mass, pI, peptide mapping, pH optimum, and effect of inhibitors, suggested that the two DAPs purified in this work are distinct enzymes and do not belong to any of the previously reported DAP classes.
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PMID:Two types of novel dipeptidyl aminopeptidases from Pseudomonas sp. strain WO24. 889 31

Dipeptidyl peptidase I (DPPI) or cathepsin C is the physiological activator of groups of serine proteases from immune and inflammatory cells vital for defense of an organism. The structure presented shows how an additional domain transforms the framework of a papain-like endopeptidase into a robust oligomeric protease-processing enzyme. The tetrahedral arrangement of the active sites exposed to solvent allows approach of proteins in their native state; the massive body of the exclusion domain fastened within the tetrahedral framework excludes approach of a polypeptide chain apart from its termini; and the carboxylic group of Asp1 positions the N-terminal amino group of the substrate. Based on a structural comparison and interactions within the active site cleft, it is suggested that the exclusion domain originates from a metallo-protease inhibitor. The location of missense mutations, characterized in people suffering from Haim-Munk and Papillon-Lefevre syndromes, suggests how they disrupt the fold and function of the enzyme.
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PMID:Structure of human dipeptidyl peptidase I (cathepsin C): exclusion domain added to an endopeptidase framework creates the machine for activation of granular serine proteases. 1172 93

The mature bovine cathepsin C (CC) molecule is composed of four identical monomers, each proteolytically processed into three chains. Five intrachain disulfides and three nonpaired cysteine residues per monomer were identified. Beside catalytic Cys234 in the active site, free-thiol Cys331 and Cys424 were characterized. Cys424 can be classified as inaccessible buried residue. Selective modification of Cys331 results in dissociation of native CC tetramer into dimers. The 3D homology-based model of the CC catalytic core suggests that Cys331 becomes exposed as the activation peptide is removed during procathepsin C activation. The model further shows that exposed Cys331 is surrounded by a surface hydrophobic cluster, unique to CC, forming a dimer-dimer interaction interface. Substrate/inhibitor recognition of the active site in the CC dimer differs significantly from that in the native tetramer. Taken together, a mechanism is proposed that assumes that the CC tetramer formation results in a site-specific occlusion of endopeptidase-like active site cleft of each CC monomeric unit. Thus, tetramerization provides for the structural basis of the dipeptidyl peptidase activity of CC through a substrate access-limiting mechanism different from those found in homologous monomeric exopeptidases cathepsin H and B. In conclusion, the mechanism of tetramer formation as well as specific posttranslational processing segregates CC in the family of papain proteases.
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PMID:Free-thiol Cys331 exposed during activation process is critical for native tetramer structure of cathepsin C (dipeptidyl peptidase I). 1191 36

The Angiotensin I converting enzyme (ACE, EC 3.4.14.1, kininase II) and neutral endopeptidases (NEP, NEP 24.11) are mechanistically related metallopeptidases. They play a key role in the regulation of blood pressure, body fluid homeostasis and cell growth. Therefore, they are implicated in the pathogenesis of arterial hypertension, congestive heart failure, left ventricular remodeling after myocardial infarction and other cardiovascular diseases. Furthermore, since these two metallopeptidases possess some subsite and substrate similarities, as indicated by their interaction with certain mercaptoalkanoyl inhibitors, they are regarded as an important common target for pharmacological inhibition with a single drug. MDL 100240 is a pro-drug that, upon conversion to MDL 100173, acts as a potent dual inhibitor of ACE and NEP with a balanced activity on both enzymes. Only very limited pharmacokinetic studies with MDL 100240 have been published. These studies used a high pressure liquid chromatography method with UV absorbance detection to quantify the drug. According to the studies in dogs the terminal t(1/2) of MDL 100173 was 35.7 h. The area under the curve for total MDL 100173 was nearly 10-fold greater than the sum of the areas under the curve for MDL 100240 and for unconjugated MDL 100173. These results support the hypothesis that MDL 100240 is hydrolyzed in plasma to the active thiol, MDL 100173, which is rapidly conjugated with endogenous plasma thiols thus providing a pathway for elimination. Studies in vivo in experimental models of hypertension and congestive heart failure confirmed the vasodilatory and natriuretic effects of MDL, which appear to be independent of the degree of activation of the renin-angiotensin-aldosterone system. In addition, MDL 100240 showed an impressive effectiveness both in preventing and in regressing hypertension-induced vascular remodeling and cardiac hypertrophy. Accordingly, MDL 100240 is being developed for the treatment of cardiovascular diseases, including hypertension and congestive heart failure. If the promises of this novel therapeutic strategy are fulfilled, clinical trials are expected to demonstrate advantages of MDL 100240 over pure ACE inhibitors.
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PMID:Dual ACE and NEP inhibitors: a review of the pharmacological properties of MDL 100240. 1259 17

Peptidases are essential for the establishment and survival of the medically important parasite, Schistosoma mansoni. This helminth expresses a number of gut-associated peptidases that degrade host blood proteins, including hemoglobin, as a means of nutrition. Using irreversible affinity probes, we demonstrate that S. mansoni cathepsin B-like endopeptidase 1 (SmCB1) is the most abundant papain family cysteine peptidase in both the parasite gut and somatic extracts. SmCB1 zymogen (SmCB1pm) was functionally expressed in Pichia pastoris (4-11mgl(-1)). Monospecific and immunoselected antibodies raised against SmCB1pm localized the enzyme exclusively to the gut lumen and surrounding gastrodermis of adult worms. Recombinant SmCB1pm was unable to catalyze its activation, even at low pH. However, recombinant S. mansoni asparaginyl endopeptidase (SmAE), another gut-associated cysteine peptidase, processed and activated SmCB1pm in trans. Consistent with the known specificity of AEs, processing occurred on the carboxyl side of an asparagine residue, two residues upstream of the start of the mature SmCB1 sequence. The remaining pro-region dipeptide was removed by rat cathepsin C (dipeptidyl-peptidase I)-an action conceivably performed by an endogenous cathepsin C in vivo. The activated recombinant SmCB1 is biochemically identical to the native enzyme with respect to dipeptidyl substrate kinetics and pH profiles. Also, the serum proteins, hemoglobin, serum albumin, IgG, and alpha-2 macroglobulin were efficiently degraded. Further, a novel application of an assay to measure the peptidyl carboxypeptidase activity of SmCB1 and other cathepsins B was developed using the synthetic substrate benzoyl-glycinyl-histidinyl-leucine (Bz-Gly-His-Leu). This study characterizes the major digestive cysteine peptidase in schistosomes and defines novel trans-processing events required to activate the SmCB1 zymogen in vitro which may facilitate the digestive process in vivo.
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PMID:Functional expression and characterization of Schistosoma mansoni cathepsin B and its trans-activation by an endogenous asparaginyl endopeptidase. 1296 13

Dipeptidyl aminopeptidase 1 (DPAP1) is an essential food vacuole enzyme with a putative role in hemoglobin catabolism by the erythrocytic malaria parasite. Here, the biochemical properties of DPAP1 have been investigated and compared to those of the human ortholog cathepsin C. To facilitate the characterization of DPAP1, we have developed a method for the production of purified recombinant DPAP1 with properties closely resembling those of the native enzyme. Like cathepsin C, DPAP1 is a chloride-activated enzyme that is most efficient in catalyzing amide bond hydrolysis at acidic pH values. The monomeric quaternary structure of DPAP1 differs from the homotetrameric structure of cathepsin C, which suggests that tetramerization is required for a cathepsin C-specific function. The S1 and S2 subsite preferences of DPAP1 and cathepsin C were profiled with a positional scanning synthetic combinatorial library. The S1 preferences bore close similarity to those of other C1-family cysteine peptidases. The S2 subsites of both DPAP1 and cathepsin C accepted aliphatic hydrophobic residues, proline, and some polar residues, yielding a distinct specificity profile. DPAP1 efficiently catalyzed the hydrolysis of several fluorogenic dipeptide substrates; surprisingly, however, a potential substrate with a P2-phenylalanine residue was instead a competitive inhibitor. Together, our biochemical data suggest that DPAP1 accelerates the production of amino acids from hemoglobin by bridging the gap between the endopeptidase and aminopeptidase activities of the food vacuole. Two reversible cathepsin C inhibitors potently inhibited both recombinant and native DPAP1, thereby validating the use of recombinant DPAP1 for future inhibitor discovery and characterization.
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PMID:Biochemical characterization of Plasmodium falciparum dipeptidyl aminopeptidase 1. 2083 9