Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.15.1 (ACE)
 18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mammalian angiotensin-converting enzyme (ACE; EC 3.4.15.1) is one of several proteins that exist in both membrane-bound and soluble forms as a result of a post-translational proteolytic processing event. For ACE we have previously identified a metalloprotease (secretase) responsible for this proteolytic cleavage. The effect of a range of structurally related zinc metalloprotease inhibitors on the activity of the secretase has been examined. Batimastat (BB94) was the most potent inhibitor of the secretase in pig kidney microvillar membranes, displaying an IC50 of 0.47 microM, whereas TAPI-2 was slightly less potent (IC50 18 microM). Removal of the thienothiomethyl substituent adjacent to the hydroxamic acid moiety or the substitution of the P2' substituent decreased the inhibitory potency of batimastat towards the secretase. Several other non-hydroxamate-based collagenase inhibitors were without inhibitory effect on the secretase, indicating that ACE secretase is a novel zinc metalloprotease that is realted to, but distinct from, the matrix metalloproteases. The full-length amphipathic form of ACE was labelled selectively with 3-trifluoromethyl-3-(m-[125I]iodophenyl)diazirine in the membrane-spanning hydrophobic region. Although trypsin was able to cleave the hydrophobic anchoring domain from the bulk of the protein, there was no cleavage of full-length ACE by a Triton X-100-solubilized pig kidney secretase preparation when the substrate was in detergent solution. In contrast, the Triton X-100-solubilized secretase preparation released ACE from pig intestinal microvillar membranes, which lack endogenous secretase activity, and cleaved the purified amphipathic form of ACE when it was incorporated into artificial lipid vesicles. Thus the secretase has an absolute requirement for its substrate to be inserted in a lipid bilayer, a factor that might have implications for the development of cell-free assays for other membrane protein secretases. ACE secretase could be solubilized from the membrane with Triton-X-100 and CHAPS, but not with n-octyl beta-D-glucopyranoside. Furthermore trypsin could release the secretase from the membrane, implying that like its substrate, ACE, it too is a stalked integral membrane protein.
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PMID:Angiotensin-converting enzyme secretase is inhibited by zinc metalloprotease inhibitors and requires its substrate to be inserted in a lipid bilayer. 935 32

Two intramolecularly quenched fluorogenic peptides containing o-aminobenzoyl (Abz) and ethylenediamine 2,4-dinitrophenyl (EDDnp) groups at amino- and carboxyl-terminal amino acid residues, Abz-DArg-Arg-Leu-EDDnp (Abz-DRRL-EDDnp) and Abz-DArg-Arg-Phe-EDDnp (Abz-DRRF-EDDnp), were selectively hydrolyzed by neutral endopeptidase (NEP, enkephalinase, neprilysin, EC 3.4.24.11) at the Arg-Leu and Arg-Phe bonds, respectively. The kinetic parameters for the NEP-catalyzed hydrolysis of Abz-DRRL-EDDnp and Abz-DRRF-EDDnp were K(m) = 2.8 microM, kcat = 5.3 min-1, kcat/K(m) = 2 min-1 microM-1 and K(m) = 5.0 microM, kcat = 7.0 min-1, kcat/K(m) = 1.4 min-1 microM-1, respectively. The high specificity of these substrates was demonstrated by their resistance to hydrolysis by metalloproteases [thermolysin (EC 3.4.24.2), angiotensin-converting enzyme (ACE; EC 3.4.24.15)], serineproteases [trypsin (EC 3.4.21.4), alpha-chymotrypsin (EC 3.4.21.1)] and proteases present in tissue homogenates from kidney, lung, brain and testis. The blocked amino- and carboxyl-terminal amino acids protected these substrates against the action of aminopeptidases, carboxypeptidases and ACE. Furthermore, DR amino acids ensured total protection of Abz-DRRL-EDDnp and Abz-DRRF-EDDnp against the action of thermolysin and trypsin. Leu-EDDnp and Phe-EDDnp were resistant to hydrolysis by alpha-chymotrypsin. The high specificity of these substrates suggests their use for specific NEP assays in crude enzyme preparations.
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PMID:Specific fluorogenic substrates for neprilysin (neutral endopeptidase, EC 3.4.24.11) which are highly resistant to serine- and metalloproteases. 949 31

Microvascular endothelial cells (MVEC), which differ from large vessel endothelial cells, have been isolated successfully from lungs of various species, including man. However, contamination by nonendothelial cells remains a major problem in spite of several technical improvements. In view of the organ specificity of MVEC, endothelial cells should be derived from the tissue involved in the diseases one wishes to study. Therefore, to investigate some of the immunopathological mechanisms leading to acute respiratory distress syndrome (ARDS), we have attempted to isolate lung MVEC from patients undergoing thoracic surgery for lung carcinoma and patients dying of ARDS. The method described here includes four main steps: (1) full digestion of pulmonary tissue with trypsin and collagenase, (2) aggregation of MVEC induced by human plasma, (3) Percoll density centrifugation, and (4) selection and transfer of MVEC after local digestion with trypsin/EDTA under light microscopy. Normal and ARDS-derived lung MVEC purified by this technique presented contact inhibition (i.e., grew in monolayer), and expressed classical endothelial markers, including von Willebrand factor (vWF), platelet endothelial cell adhesion molecule 1(PECAM-1, CD31), and transcripts for the angiotensin converting enzyme (ACE). The cells also formed capillarylike structures, took up high levels of acetylated low-density lipoprotein (Ac-LDL), and exhibited ELAM-1 inducibility in response to TNF. Contaminant cells, such as fibroblasts, smooth muscle cells, or pericytes, were easily recognized on the basis of morphology and were eliminated by selection of plasma-aggregated cells under light microscopy. The technique presented here allows one to study the specific involvement and contribution of pulmonary endothelium in various lung diseases.
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PMID:An improved method for isolation of microvascular endothelial cells from normal and inflamed human lung. 971 12

1. Subcutaneous injection of sodium deoxycholic acid into the anterior of the back of male ddY mice elicited dose-dependent scratching of the injected site with the forepaws and hindpaws. 2. Up to 100 microg of sodium deoxycholic acid induced no significant increase in vascular permeability at the injection site as assessed by a dye leakage method. 3. Bradykinin (BK) B2 receptor antagonists, FR173657 and Hoe140, significantly decreased the frequency of scratching induced by sodium deoxycholic acid. 4. Treatment with aprotinin to inhibit tissue kallikrein reduced the scratching behaviour induced by sodium deoxycholic acid, whereas treatment with soybean trypsin inhibitor to inhibit plasma kallikrein did not. 5. Although injection of kininase II inhibitor, lisinopril together with sodium deoxycholic acid did not alter the scratching behaviour, phosphoramidon, a neutral endopeptidase inhibitor, significantly increased the frequency of scratching. 6. Homogenates of the skin excised from the backs of mice were subjected to gel-filtration column chromatography followed by an assay of kinin release by trypsin from each fraction separated. Less kinin release from the fractions containing kininogen of low molecular weight was observed in the skin injected with sodium deoxycholic acid than in normal skin. 7. The frequency of scratching after the injection of sodium deoxycholic acid in plasma kininogen-deficient Brown Norway Katholiek rats was significantly lower than that in normal rats of the same strain, Brown Norway Kitasato rats. 8. These results indicate that BK released from low-molecular-weight kininogen by tissue kallikrein, but not from high-molecular-weight kininogen by plasma kallikrein, may be involved in the scratching behaviour induced by the injection of sodium deoxycholic acid in the rodent.
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PMID:Reduction of sodium deoxycholic acid-induced scratching behaviour by bradykinin B2 receptor antagonists. 1005 Nov 36

We investigated whether daphnodorin A, daphnodorin B and daphnodorin C inhibited human chymase-dependent angiotensin II-forming activity. Although the structures of these compounds are very similar, daphnodorin A completely inhibited angiotensin II formation generated by chymase, while daphnodorin B partially inhibited and daphnodorin C did not. On the other hand, these daphnodorins did not affect angiotensin converting enzyme-dependent angiotensin II formation. Furthermore, these daphnodorins did not inhibit purified human tryptase, which, like chymase, is contained in mast cells. Therefore, daphnodorin A, but not daphnodorin B and daphnodorin C, may specifically inhibit the chymase-dependent angiotensin II formation, and such differences between inhibitory effects of these compounds to human chymase may be useful for the development of human chymase inhibitor.
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PMID:Effects of daphnodorin A, daphnodorin B and daphnodorin C on human chymase-dependent angiotensin II formation. 1035 87

The aim of this study was to identify whey-derived peptides with angiotensin I-converting enzyme (ACE) inhibitory activity. The bovine whey proteins alpha-lactalbumin and beta-lactoglobulin were hydrolysed with pepsin, trypsin, chymotrypsin, pancreatin, elastase or carboxypeptidase alone and in combination. The total hydrolysates were fractionated in a two step ultrafiltration process, first with a 30 kDa membrane and then with a 1 kDa membrane. Inhibition of ACE was analysed spectrophotometrically. The peptides were isolated by chromatography and identified by mass and sequencing analysis. The most potent inhibitory peptides were synthesized by the 9-fluorenylmethoxycarbonyl solid phase method. Inhibition of ACE was observed after hydrolysis with trypsin alone, and with an enzyme combination containing pepsin, trypsin and chymotrypsin. Whey protein digests gave a 50% inhibition (IC50) of ACE activity at concentration ranges within 345-1733 micrograms/ml. The IC50 values for the 1-30 kDa fractions ranged from 485 to 1134 micrograms/ml and for the < 1 kDa fraction from 109 to 837 mg/ml. Several ACE-inhibitory peptides were isolated from the hydrolysates by reversed-phase chromatography, and the potencies of the purified peptide fractions had IC50 values of 77-1062 microM. The ACE-inhibitory peptides identified were alpha-lactalbumin fractions (50-52), (99-108) and (104-108) and beta-lactoglobulin fractions (22-25), (32-40), (81-83), (94-100), (106-111) and (142-146).
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PMID:Angiotensin I-converting enzyme inhibitory properties of whey protein digests: concentration and characterization of active peptides. 1071 43

Possible involvement of mast cells in pulmonary sarcoidosis has been suggested, however whether mast cells are involved in cutaneous sarcoidosis remains unknown. We undertook a morphological study of mast cells in the lesional skin from 17 patients with cutaneous sarcoidosis using immunohistochemical methods. Mast cells were present in non-parenchymal fibrous areas, but not in granulomatous areas, in the biopsy specimens from the cutaneous lesions. However, there were no significant differences between the number of mast cells in the lesional skin and that in non-lesional skin from the patients. Mast cells containing substantial quantities of both tryptase and chymase (MC(TC) cells) were present in 41% of the patients, and cells containing tryptase but not chymase (MC(T) cells) were present in 59% of patients. All patients of the former group showed systemic manifestations of the disease concomitantly. Serum angiotensin I-converting enzyme levels were elevated in 71.4% of the former group, and in 30% of the latter group. This study for the first time demonstrated that mast cells were present in non-parenchymal fibrous areas of the cutaneous lesions of sarcoidosis, and the mast cell subtypes may be related to systemic manifestations.
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PMID:Mast cells in the cutaneous lesions of sarcoidosis: their subtypes and the relationship to systemic manifestations. 1096 Jul 79

Agonist-induced endocytosis and/or down-regulation have been evaluated using green fluorescent protein (GFP) conjugates of the rabbit bradykinin (BK) B2 receptor (B2R). COS-1 cells transiently transfected with vectors coding for either of two rabbit B2R fluorescent variants, B2R-GFP and B2R-GFP DeltaS/T (with previously identified Ser/Thr phosphorylation sites in the C-terminal tail mutated to Ala), exhibited specific and saturable binding (K(D) in the lower nM range). The acute addition of BK (10-100 nM) to HEK 293 cells stably expressing B2R-GFP in the presence of cycloheximide was rapidly followed by translocation of the surface receptors into the cells, with essentially complete recycling of the surface receptors in 1 to 3 h (confocal microscopy, cell fractionation). Adding captopril to inhibit angiotensin I-converting enzyme activity increased the half-life of BK in the culture medium (enzyme immunoassay) and, accordingly, promoted B2R-GFP internalization for at least 3 h. However, agonist-induced down-regulation was not observed under conditions optimal for endocytosis (microscopy, immunoblot using anti-GFP antibodies). In contrast, B2R-GFP was partially degraded following a short treatment of cells with trypsin. B2R-GFP internalized following agonist treatment was colocalized with fluorescent transferrin, supporting translocation of the receptor to recycling endosomes. B2R-GFP DeltaS/T failed to translocate into the cells following treatment with BK, but exhibited at baseline an altered subcellular distribution relative to B2R-GFP. The agonist BK promotes B(2)R receptor endocytosis followed by recycling to the cell surface, but does not promote receptor down-regulation in the heterologous system that we used here. Digestion initiated by extracellular proteases may be involved in pathological B2R down-regulation, as suggested by the simulation involving trypsin.
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PMID:Bradykinin B(2) receptor endocytosis, recycling, and down-regulation assessed using green fluorescent protein conjugates. 1125 23

A strong and constitutive angiotensin converting enzyme- or ACE-like activity was demonstrated in the hemolymph of the adult grey fleshfly Neobellieria bullata. In a competition assay, the N. bullata trypsin modulating oostatic factor (Neb-TMOF) was confirmed to be an in vitro substrate for this circulating Neb-ACE. Oral uptake of captopril, a selective and specific inhibitor of ACE, resulted in a complete phenotypic knockout of circulating ACE activity. When compared with control animals, captopril-fed female flies showed an increase in the liver meal-induced trypsin peak in the midgut and elevated levels of protein meal-induced yolk polypeptides in the hemolymph. The latter effect was not due to a slower vitellogenin uptake by the ovaries, because oocyte growth was not affected by the captopril treatment. The apparent synergism between the demonstrated ACE functionality and the previously reported effects of the oostatic peptide Neb-TMOF are discussed in the context of our recent finding that Neb-TMOF represents a prime candidate for being the first known in vivo substrate for circulating insect ACE. Arch.
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PMID:Captopril, a specific inhibitor of angiotensin converting enzyme, enhances both trypsin and vitellogenin titers in the grey fleshfly Neobellieria bullata. 1141 34

In order to clarify the potential physiological function of royal jelly (RJ), we report here the gastrointestinal enzyme production of antihypertensive peptides from RJ. Intact RJ and its protein fraction did not retard the action of angiotensin I-converting enzyme (ACE) activity at all. However, development of ACE inhibition power of RJ was newly observed by pepsin hydrolysis (IC(50)=0.358 mg protein/mL), and the subsequent trypsin and chymotrypsin hydrolyses (IC(50)=0.099 mg protein/mL). Single oral administration of this gastrointestinal RJ hydrolysate (1 g/kg dose) in 10-week spontaneously hypertensive rat resulted in a significant reduction of systolic blood pressure of 22.7 plus minus 3.6 mmHg at 2 hr (P<0.05 vs. 0 hr by one-way ANOVA, n=7). Then, the RJ hydrolysate was fractionated with gel permeation chromatography to obtain the di- and tri-peptides (DTP) fraction. As a result of isolation from the DTP fraction by reversed phase-high performance liquid chromatography, eleven ACE inhibitory peptides were isolated from the DTP-RJ hydrolysate. Some of the ACE inhibitors were derived from the RJ-glycoprotein; eight peptides with the IC(50) value of <10 &mgr;M were identified from natural resources for the first time. Consequently, RJ protein was thought to be a good resource of ACE inhibitory peptides produced by the gastrointestinal enzyme hydrolyses.
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PMID:Gastrointestinal enzyme production of bioactive peptides from royal jelly protein and their antihypertensive ability in SHR. 1183 23


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