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This article is from PLoS ONE , volume 9 . Abstract ACE inhibitor drugs decrease mortality by up to one-fifth in cardiovascular patients. Surprisingly, there are reports dating back to 1979 suggesting the existence of endogenous ACE inhibitors. Here we investigated the clinical significance of this potential endogenous ACE inhibition.ACE concentration and activity was measured in patient's serum samples (n = 151). ACE concentration was found to be in a wide range (47–288 ng/mL). ACE activity decreased with the increasing concentration of the serum albumin (HSA): ACE activity was 56±1 U/L in the presence of 2.4±0.3 mg/mL HSA, compared to 39±1 U/L in the presence of 12±1 mg/mL HSA (values are mean±SEM). Effects of the differences in ACE concentration were suppressed in human sera: patients with ACE DD genotype exhibited a 64% higher serum ACE concentration (range, 74–288 ng/mL, median, 155.2 ng/mL, n = 52) compared to patients with II genotype (range, 47–194 ng/mL, median, 94.5 ng/mL, n = 28) while the difference in ACE activities was only 32% (range, 27.3–59.8 U/L, median, 43.11 U/L, and range 15.6–55.4 U/L, median, 32.74 U/L, respectively) in the presence of 12±1 mg/mL HSA. No correlations were found between serum ACE concentration (or genotype) and cardiovascular diseases, in accordance with the proposed suppressed physiological ACE activities by HSA (concentration in the sera of these patients: 48.5±0.5 mg/mL) or other endogenous inhibitors.Main implications are that (1) physiological ACE activity can be stabilized at a low level by endogenous ACE inhibitors, such as HSA; (2) angiotensin II elimination may have a significant role in angiotensin II related pathologies.

This article is from International Journal of Molecular Sciences , volume 15 . Abstract The objectives of the present study were two-fold: first, to detect whether salmon protein fractions possess angiotensin I-converting enzyme (ACE) inhibitory properties and whether salmon proteins can release ACE inhibitory peptides during a sequential in vitro hydrolysis (with commercial porcine enzymes) and ex vivo digestion (with human gastrointestinal enzymes). Secondly, to evaluate the ACE inhibitory activity of generated hydrolysates. A two-step ex vivo and in vitro model digestion was performed to simulate the human digestion process. Salmon proteins were degraded more efficiently by porcine enzymes than by human gastrointestinal juices and sarcoplasmic proteins were digested/hydrolyzed more easily than myofibrillar proteins. The ex vivo digested myofibrillar and sarcoplasmic duodenal samples showed IC50 values (concentration required to decrease the ACE activity by 50%) of 1.06 and 2.16 mg/mL, respectively. The in vitro hydrolyzed myofibrillar and sarcoplasmic samples showed IC50 values of 0.91 and 1.04 mg/mL, respectively. Based on the results of in silico studies, it was possible to identify 9 peptides of the ex vivo hydrolysates and 7 peptides of the in vitro hydrolysates of salmon proteins of 11 selected peptides. In both types of salmon hydrolysates, ACE-inhibitory peptides IW, IY, TVY and VW were identified. In the in vitro salmon protein hydrolysates an ACE-inhibitory peptides VPW and VY were also detected, while ACE-inhibitory peptides ALPHA, IVY and IWHHT were identified in the hydrolysates generated with ex vivo digestion. In our studies, we documented ACE inhibitory in vitro effects of salmon protein hydrolysates obtained by human and as well as porcine gastrointestinal enzymes.

This article is from Iranian Journal of Pharmaceutical Research : IJPR , volume 12 . Abstract Ipomoea reniformis Roxb. (Convolvulaceae) is a small, weedy herb used for the management of cardiac problems in traditional systems of medicine in India and Pakistan. Objective of the present study was to investigate the hypotensive, diuretic and angiotensin converting enzyme (ACE) inhibitory activities of the aqueous-methanol (30:70) crude extract of the dried aerial parts of I. reniformis (Ir.Cr.) in rats. To record blood pressure lowering effects of the Ir.Cr, different doses of the extract were administered through jugular vein to the ketamine-diazepam anesthetized normotensive rats and blood pressure was recorded via carotid artery. ACE inhibitory activity of the extract was studied in-vitro; using hippuryl-l-histidyl-l-leucine as substrate, the product hippurate was quantified spectrophotometrically after reacting with cyanuric chloride/dioxane reagent. Effects of intraperitoneal administration of the extract on urine and urinary electrolyte excretion were also investigated in rats. The extract (Ir.Cr.) produced 21.51 ± 3.41, 28.99 ± 2.30, 53.34 ± 0.88 and 61.71 ± 3.37% fall in mean arterial blood pressure of the anesthetized rats at the doses of 0.1, 0.3, 1.0 and 3.0 mg/Kg, respectively. Ir.Cr. was found to have serum ACE inhibitory activity, with IC50 value of 422 ± 21.16 μg/mL. The extract also increased urine volume and urinary Na+ excretion significantly at the doses of 30 and 50 mg/Kg in rats. The study concludes that the crude extract of Ipomoea reniformis (Ir.Cr.) has hypotensive, ACE inhibitory and diuretic activities, which provide the scientific justification for the traditional uses of the plant as cardioprotective, antihypertensive and diuretic remedy.

This article is from BMC Complementary and Alternative Medicine , volume 13 . Abstract Background: Ganoderma lucidum has been purported as a potent remedy in the treatment and prevention of several ailments, including hypertension. This study aimed to explore the anti-ACE potential of protein fractions from the mycelia of G. lucidum. Methods: Ganoderma lucidum mycelia were cultivated by submerged fermentation in a liquid medium containing brown sugar and spent brewer’s yeast. Intracellular proteins were fractionated from mycelia crude water extract by ammonium sulphate precipitation, and their angiotensin converting enzyme inhibitory activity was evaluated. The potential anti-ACE protein fractions were further separated by RP-HPLC and characterised using proteomics platforms. Results: Preliminary result demonstrated that the mycelia crude water extract inhibited ACE at IC50 value of 1.134 ± 0.036 mg/mL. Following protein fractionation and HPLC purification, the presence of highly potential anti-ACE proteins with the IC50 values less than 200 μg/mL was detected. Characterisation of these proteins demonstrated the presence of four different antihypertensive-related proteins involved in the regulation of blood pressure through different mechanisms. Conclusions: This study suggests that the mycelia of G. lucidum has high potential in lowering blood pressure level due to the presence of several antihypertensive-related proteins such as cystathionine beta synthase-like protein, DEAD/DEAH box helicase-like protein, paxillin-like protein, and alpha/beta hydrolase-like protein.

One of the world's silent killer diseases is hypertension. Hypertension occurs when angiotensin I is converted to angiotensin II, causing vasoconstriction and decreasing sodium and water excretion. The mechanism of angiotensin I conversion to angiotensin II appears in the presence of the Angiotensin-Converting Enzyme (ACE). Dayak onion is widely used as an antihypertensive in traditional medicine. This study aims to identify secondary metabolites, determine total flavonoid content, determine extract quality parameters, and ACE inhibitory activity of the Dayak onion herb. Dayak onion herb was extracted with 70% ethanol by kinetic maceration, followed by phytochemical screening, extract quality assessment, and ACE inhibitory test. The results show that the Dayak onion extract has a good properties with total ash content of 4.49%, water-soluble ash content of 4.00%, acid-insoluble ash content of 0.41%, drying shrinkage of 9.70%, water content of 5.72%, solvent residue of 0.67%, Pb heavy metal content of 0.2908 mg/kg, Cd heavy metal content of 0.0880 mg/kg, total plate number ≤103 colonies/g, and yeast mold numbers ≤103 colonies/g. Dayak onions herbs extract contains flavonoid, alkaloid, saponin, tannin, triterpenoid, quinone, steroid and essential oil compounds. The total flavonoid content was 2.24% and the IC50 in ACE inhibitory test was 98.5 ± 0.77 ppm, making it two times more potent than Veronica biloba and Schoenoplectus triqueter. The result of this study indicates that the Dayak onion herb can be used as an alternative for antihypertensive treatment.

This article is from The Journal of Biological Chemistry , volume 289 . Abstract Background: The angiotensin-1-converting enzyme (ACE) is a zinc protease unique in its chloride ion dependence.Results: Key substrate interactions with the catalytic site affect the structure and thermodynamics of ACE, which modulate chloride ion-dependent hydrolysis.Conclusion: Substrate composition influences chloride affinity in ACE.Significance: The interdependence of ACE substrate composition, structure, and thermodynamics influence its chloride ion activation in biology.

This article is from PLoS ONE , volume 9 . Abstract About 8% of the adult population is taking angiotensin-converting enzyme (ACE) inhibitors to treat cardiovascular disease including hypertension, myocardial infarction and heart failure. These drugs decrease mortality by up to one-fifth in these patients. We and others have reported previously that endogenous inhibitory substances suppress serum ACE activity, in vivo, similarly to the ACE inhibitor drugs. Here we have made an effort to identify this endogenous ACE inhibitor substance. ACE was crosslinked with interacting proteins in human sera. The crosslinked products were immunoprecipitated and subjected to Western blot. One of the crosslinked products was recognized by both anti-ACE and anti-HSA (human serum albumin) antibodies. Direct ACE-HSA interaction was confirmed by binding assays using purified ACE and HSA. HSA inhibited human purified (circulating) and human recombinant ACE with potencies (IC50) of 5.7±0.7 and 9.5±1.1 mg/mL, respectively. Effects of HSA on the tissue bound native ACE were tested on human saphenous vein samples. Angiotensin I evoked vasoconstriction was inhibited by HSA in this vascular tissue (maximal force with HSA: 6.14±1.34 mN, without HSA: 13.54±2.63 mN), while HSA was without effects on angiotensin II mediated constrictions (maximal force with HSA: 18.73±2.17 mN, without HSA: 19.22±3.50 mN). The main finding of this study is that HSA was identified as a potent physiological inhibitor of the ACE. The enzymatic activity of ACE appears to be almost completely suppressed by HSA when it is present in its physiological concentration. These data suggest that angiotensin I conversion is limited by low physiological ACE activities, in vivo.

Phenolic compounds are important products from secondary metabolism in plants. These cannot be synthesized in the human body and are mainly taken from plant source. Cereal grains are important sources of dietary polyphenols. Phenolic compounds are the main source of antioxidant that reduces the incidence of chronic diseases including heart disease, blood cholesterol, blood pressure, diabetic etc. Angiotensin-converting enzyme (ACE) inhibitors are medications that help to relax the veins and arteries to lower blood pressure. The aim of this experiment was to study the phenolic compounds identified in eight cereal grain (white rice, viscosity rice, brown rice, black rice, sticky rice, oatmeal, millet and sorghum) with their antioxidant and angiotensin-converting enzyme (ACE) inhibitory activity level. The phenolic content determined according to the Folin Ciocalteu’s method. Black rice contains maximum phenolic compound (94.90 mg Tannic acid equivalent/g of extract) that was statistically different from other cereal grains (p<0.05) but followed by oatmeal and sorghum (58.82 and 58.57 mg Tannic acid equivalent/g of extract respectively). Antioxidant activities were comparatively assessed by ABTS (2, 2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid) free radical decolorization assay method. It was observed that maximum cereal grain has no antioxidant activity. Among eight cereal grain, only black rice, oatmeal and sorghum showed considerable free radical scavenging capacity by ABTS radical. Angiotensin-converting enzyme (ACE) inhibition rate was determined by using L-hippuryl-histidyl-leucine (HHL). Maximum angiotensin-converting enzyme (ACE) inhibitory activity was also found in black rice (66.80%) followed by oatmeal (48.62%) and sorghum (37.45%). It might be concluded that polyphenol content was closely related to antioxidant activity and angiotensin-converting enzyme (ACE) inhibitor activity. Black rice, oatmeal and sorghum can be used as functional food for their high phenolic content, antioxidant activity as well as angiotensin-converting enzyme (ACE) inhibitory activity against chronic diseases.

This article is from The Open Medicinal Chemistry Journal , volume 7 . Abstract A main target in the treatment of hypertension is the angiotensin-converting enzyme (ACE). This enzyme is responsible for producing angiotensin II, a potent vasoconstrictor. Therefore, one of the targets in the treatment of hypertension is to inhibit ACE activity. Hence, this study’s aim is to use computational studies to demonstrate that the proposed heterocyclic compounds have a molecular affinity for ACE and that, furthermore, these heterocyclic compounds are capable of inhibiting ACE activity, thus avoiding the production of the vasopressor Angiotensin II. All this using computer-aided drug design, and studying the systems, with the proposed compounds, through molecular recognition process and compared with the compounds already on the market for hypertension.

This article is from PLoS ONE , volume 9 . Abstract Angiotensin-converting enzyme (ACE) inhibitors represent the fifth most often prescribed drugs. ACE inhibitors decrease 5-year mortality by approximately one-fifth in cardiovascular patients. Surprisingly, there are reports dating back to 1979 suggesting the existence of endogenous ACE inhibitors, which endogenous inhibitory effects are much less characterized than that for the clinically administered ACE inhibitors. Here we aimed to investigate this endogenous ACE inhibition in human sera. It was hypothesized that ACE activity is masked by an endogenous inhibitor, which dissociates from the ACE when its concentration decreases upon dilution. ACE activity was measured by FAPGG hydrolysis first. The specific (dilution corrected) enzyme activities significantly increased by dilution of human serum samples (23.2±0.7 U/L at 4-fold dilution, 51.4±0.3 U/L at 32-fold dilution, n = 3, p = 0.001), suggesting the presence of an endogenous inhibitor. In accordance, specific enzyme activities did not changed by dilution when purified renal ACE was used, where no endogenous inhibitor was present (655±145 U/L, 605±42 U/L, n = 3, p = 0.715, respectively). FAPGG conversion strongly correlated with angiotensin I conversion suggesting that this feature is not related to the artificial substrate. Serum samples were ultra-filtered to separate ACE (MW: 180 kDa) and the hypothesized inhibitor. Filtering through 50 kDa filters was without effect, while filtering through 100 kDa filters eliminated the inhibiting factor (ACE activity after

TITLE : 2010 JUN 22 Angiotensin-converting enzyme 2 (ACE2) proteins of different bat species confer variable susceptibility to SARS-CoV entry Main Work TITLE :   Angiotensin-converting enzyme 2 (ACE2) proteins of different bat species confer variable susceptibility to SARS-CoV entry Abstract : The discovery of SARS-like coronavirus in bats suggests that bats could be the natural reservoir of SARSCoV. However, previous studies indicated the angiotensin-converting enzyme 2 (ACE2) protein, a known SARS-CoV receptor, from a horseshoe bat was unable to act as a functional receptor for SARS-CoV. Here, we extended our previous study to ACE2 molecules from seven additional bat species and tested their interactions with human SARS-CoV spike protein using both HIV-based pseudotype and live SARS-CoV infection assays. The results show that ACE2s of Myotis daubentoni and Rhinolophus sinicus support viral entry mediated by the SARS-CoV S protein, albeit with different efficiency in comparison to that of the human ACE2. Further, the alteration of several key residues either decreased or enhanced bat ACE2 receptor efficiency, as predicted from a structural modelling study of the different Original ref: DOI 10.1007/s00705-010-0729-6 (Arch Virol (2010) 155:1563–1569) Original file name: Hou2010_Article_Angiotensin-convertingEnzyme2A.pdf Main Work Source URL : https://link.springer.com/content/pdf/10.1007%2Fs00705-010-0729-6.pdf AUTHOR : Yuxuan Hou, Cheng Peng,   Meng Yu,   Yan Li, Zhenggang Han, Fang Li, Lin-Fa Wang, Zhengli Shi   PUBLISHED : Received: 21 April 2010 / Accepted: 12 June 2010 / Published online: 22 June 2010 FILE SIZE :   571 kb PAGES : 7 TAGS : ACE2, SARS-CoV, Coronavirus, PDF, ARCHIVE FILE NAME :   2010JUN22_Angiotensin_converting_enzyme_2_(ACE2)_proteins_of_different_bat_species_confer_variable_susceptibility_to_SARS_CoV_entry DOCUMENT FILE NAME :   2010JUN22_Angiotensin_converting_enzyme_2_(ACE2)_proteins_of_different_bat_species_confer_variable_susceptibility_to_SARS_CoV_entry.pdf MS WORD FILE NAME :   2010JUN22_Angiotensin_converting_enzyme_2_(ACE2)_proteins_of_different_bat_species_confer_variable_susceptibility_to_SARS_CoV_entry.docx ARCHIVE UPLOADED URL: