Optimisation and validation of an angiotensin-converting enzyme inhibition assay for the screening of bioactive peptides (original) (raw)
Related papers
Journal of Food Science, 2000
Angiotensin I-converting enzyme (ACE)-inhibitory peptides from the thermolysin digest of chicken muscle and the peptic digest of ovalbumin were isolated. However, some of them failed to show antihypertensive activity in spontaneously hypertensive rats (SHR). To clarify this discrepancy, ACE-inhibitory peptides from various sources were preincubated with ACE before measurement of ACE-inhibitory activity and classified into 3 groups: (1) inhibitor type, IC 50 values of peptides that are not affected after preincubation with ACE;( 2) substrate type, peptides that are hydrolyzed by ACE to give peptides with weaker activity; and (3) prodrug-type inhibitor, these peptides are converted to true inhibitors by ACE or gastrointestinal proteases. Peptides belonging to the 1st and the 3rd groups exert antihypertensive activities even after oral administration in SHR.
Nutrition Research, 2004
Angiotensin I-converting enzyme (ACE) catalyzes the conversion of angiotensin I to vasoconstrictor angiotensin II, and also inactivates the antihypertensive vasodilator bradykinin. Inhibition of ACE mainly results in an overall antihypertensive effect. Peptides derived from food proteins can have ACE inhibiting properties. This article reviews the ACE inhibitory peptides derived from different food proteins. Some of the ACE inhibitory peptides exhibit significant antihypertensive effects. However, the inhibitory potencies of these peptides on ACE activity do not always correlate with their antihypertensive activities. Some peptides with high inhibitory activity on this enzyme in vitro have no blood pressure lowering effects, whereas some peptides with low inhibitory activity on this enzyme in vitro have such effects. The possible mechanisms for this conflicting phenomenon between inhibitory activity and antihypertensive effect, the structure-activity relationships, and the potential use prospect of these peptides in the development of a novel functional food for preventing hypertension as well as therapeutic purposes, are also discussed.
Current Pharmaceutical Design, 2009
The existence of endogenous bioactive protein or peptide with angiotensin-converting enzyme (ACE) inhibitory activity in snakehead fish fillet is promising to be investigated. The purposes of this research were to extract ACE inhibitory endogenous protein or peptide from snakehead fish fillet and to fractionate the active compounds using ultrafiltration. The extraction employed two solvents, i.e. aquadest and 50% ethanol. Fractionation was conducted using ultrafiltration membranes of 10,000; 5,000 and 3,000 Molecular W eight Cut Off (MW CO) to separate the protein or peptide into the sizes of >10 kDa, 5-10 kDa, 3-5 kDa and <3 kDa. The parameters observed were protein and peptide content, ACE inhibitory activity (in vitro) and also protein and peptide profiles. The result revealed that the snakehead fish fillet contained ACE inhibitory endogenous bioactive protein or peptide. The 50% ethanol was more effective in extracting peptide of <10 kDa than the aquadest. Yet, the aquadest was better in extracting higher molecular weight protein of >10 kDa than the 50% ethanol. The fraction of <3 kDa by aquadest had the highest ACE inhibitor activity per g protein (7.85% inhibition of ACE per g protein). Thus, the fraction of <3 kDa aquadest is the most promising option for further research and development of natural anti-hypertension compound. From the result, snakehead fish fillet was potential to be utilized as a functional food as well as functional ingredient to fight hypertension.
Angiotensin-Converting Enzyme Inhibitory Activity
In this study, a potent angiotensin-converting enzyme (ACE)-inhibitory activity was found in a commercial kefir made from caprine milk. The low molecular mass peptides released from caseins during fermentation were mainly responsible for this activity. Sixteen peptides were identified by HPLC-tandem mass spectrometry. Two of these peptides, with sequences PYVRYL and LVYPFTGPIPN, showed potent ACE-inhibitory properties. The impact of gastrointestinal digestion on ACE-inhibitory activity of kefir peptides was also evaluated. Some of these peptides were resistant to the incubation with pepsin followed by hydrolysis with Corolase PP. The ACE-inhibitory activity after simulated digestion was similar to or slightly lower than unhydrolyzed peptides, except for peptide β-casein f(47-52) (DKIHPF), which exhibited an activity 8 times greater after hydrolysis.
… Nutrition & Food …, 2011
The aim of this study was to investigate the antihypertensive effect of a peptide fraction (PepC) obtained from a whey protein concentrate following hydrolysis by Cynara cardunculus, as well as of its fraction with MW below 3 kDa (PepCF). Both these concentrates encompassed peptides that exhibited potent in vitro inhibition of angiotensin-converting enzyme (ACE): two were released from a-lactalbumin-KGYGGVSLPEW and DKVGINYW, and one from b-lactoglobulin-DAQSAPLRVY. Methods and results: Upon oral administration, by gastric intubation, of 400 mg/kg body weight (bw) of those peptide concentrates, or 5 mg/kg bw of the corresponding synthetic peptides, to 12 wk-old spontaneously hypertensive rats (SHR), the systolic and diastolic blood pressures were monitored by the tail-cuff method-before, and 2, 4, 6, 8 and 24 h afterwards. Water and zofenopril (5 mg/kg bw)-a known ACE-inhibitor, were used as negative and positive controls, respectively. Acute administration of PepC, PepCF, KGYGGVSLPEW, DKVGINYW and DAQSAPLRVY caused antihypertensive effects in SHR; the maximum effect occurred by 4 h and 6 h after administration of the peptide concentrates and the synthetic peptides, respectively. PepC and KGYGGVSLPEW also showed ACE-inhibitory activity in vivo: the pressor effect of angiotensin I was significantly lower, and the response to bradykinin increased when the rats were pre-treated with either product. Conclusion: Our results strongly suggest that PepC will be effective as nutraceutical ingredient for the formulation of functional foods aimed at hypertension control.
Journal of Agricultural and Food Chemistry, 2007
In this study, we have identified novel antihypertensive peptides derived from egg-white proteins. The sequences YRGGLEPINF and ESIINF produced an acute blood-pressure-lowering effect in spontaneously hypertensive rats upon a single oral administration. Our results suggest that the antihypertensive action could be attributed to a vascular-relaxing mechanism that would occur in vivo independently of angiotensin I-converting enzyme (ACE) inhibition, because neither these peptides nor their main digestion fragments, except for the dipeptide YR, acted as ACE inhibitors in vitro. The vasodilator and antihypertensive activity of the sequences ESI and NF would explain the bloodpressure-lowering effect of ESIINF. With regard to YRGGLEPINF, in addition to NF, YR appeared as the main fragment responsible for its activity. The dipeptide YR, named kyotorphin and previously identified as an endogenous analgesic neuropeptide in the central nervous system, showed strong vasodilator and antihypertensive properties. The structure-activity features of the vasodilator peptides are discussed. DGSRQPV (ovotransferrin 230-236). The fragments resulting from the simulation of the gastrointestinal digestion of YRGGLEPINF and ESIINF (YRGGLEPI, YR, GGLEPI, ESI, and NF) were also synthesized. All of these peptides were obtained by conventional Fmoc solid-phase synthesis with a 431A peptide synthesizer (Applied Biosystem, Inc., Ü berlingen, Germany) according to the method described by Atherton and Sheppard (29). They were synthesized and provided by the Unitat de Pèptids of Barcelona University, and their purity (>90%) was verified in our laboratory by reversed-phase high-performance liquid chromatography-tandem mass spectrometry (RP-HPLC-MS/MS) (30). The drugs and the peptides were dissolved in distilled water for the reactivity experiments and administration to the rats.
International Journal of Peptide Research and Therapeutics, 2020
Hypertension is declared as the major risk factor of cardiovascular diseases and stroke, and the leading cause of premature deaths. ACE is a zinc dependent dipeptidyl peptidase and plays key role in controlling blood pressure via renin angiotensin system (RAS), and hence serves as the promising target for antihypertension drugs. Many food derived antihypertensive peptides have been identified recently. However, their ACE inhibitory activity, interactions and stability are not fully evaluated. Our work focused on combination of modern bioinformatics techniques for efficient evaluation of potent ACE inhibitory food peptides and understanding of interactions between ACE and inhibitory peptides. We reported novel antihypertensive peptide IQDVPS, LQPGS, VIP from date, salmon and soybean proteins respectively. Food proteins were digested in-silico to release peptides. Molecular docking studies revealed high binding affinities and interactions with ACE active site. MD simulations and Alanine Scanning were carried out to study the stability of these ACE-peptide complexes in cell like environment. The results showed that the suggested peptides competitively inhibit ACE by tightly binding to its active site, meanwhile maintaining the structural stability of the complex. ACE-LQPGS (Salmon) was found to have best binding with least structural fluctuations.
Milk protein-derived peptide inhibitors of angiotensin-I-converting enzyme
British Journal of Nutrition, 2000
Numerous casein and whey protein-derived angiotensin-I-converting enzyme (ACE) inhibitory peptides/hydrolysates have been identified. Clinical trials in hypertensive animals and humans show that these peptides/hydrolysates can bring about a significant reduction in hypertension. These peptides/hydrolysates may be classified as functional food ingredients and nutraceuticals due to their ability to provide health benefits i.e. as functional food ingredients in reducing the risk of developing a disease and as nutraceuticals in the prevention/treatment of disease.
Bioavailability of angiotensin I converting enzyme inhibitory peptides
British Journal of Nutrition, 2004
Hypertension or high blood pressure is a significant health problem worldwide. Bioactive peptides that inhibit angiotensin I converting enzyme (ACE) in the cardiovascular system can contribute to the prevention and treatment of hypertension. These ACE inhibitory peptides are derived from many food proteins, especially milk proteins. An ACE inhibitory activity in vitro does not always imply an antihypertensive effect in vivo. Even if it does, it is very difficult to establish a direct relationship between in vitro and in vivo activity. This is mainly due to the bioavailability of the ACE inhibitory peptides after oral administration and the fact that peptides may influence blood pressure by mechanisms other than ACE inhibition. To exert an antihypertensive effect after oral ingestion, ACE inhibitory peptides have to reach the cardiovascular system in an active form. Therefore, they need to remain active during digestion by human proteases and be transported through the intestinal wall into the blood. The bioavailability of some ACE inhibitory peptides has been studied. It is also known that (hydroxy)proline-containing peptides are generally resistant to degradation by digestive enzymes. Peptides can be absorbed intact through the intestine by paracellular and transcellular routes, but the potency of the bioactivity after absorption is inversely correlated to chain length. In addition, some strategies are proposed to increase the bioavailability of ACE inhibitory peptides. Further research into the bioavailability of ACE inhibitory peptides will lead to the development of more effective ACE inhibitory peptides and foods. Bioactive peptides: Hypertension: Gastrointestinal digestion: Intestinal transport * Corresponding author: Dr Willy Verstraete, fax þ 32 92 64 62 48, email willy.verstrete@UGent.be Abbreviations: ACE, angiotensin I converting enzyme; IC 50 , median inhibitory concentration; SHR, spontaneously hypertensive rat.
Le Lait, 2005
The angiotensin I converting enzyme (ACE) inhibitory activity of fermented blue mussel sauce (FBMS) was investigated. Blue mussels were fermented with 25% NaCl (w/w) at 20 degrees C for 6 months and the resultant mixture was passed through a 40-mesh sieve, desalted using an electrodialyzer and then lyophilized. The IC(50) value of FBMS for ACE activity was 1.01 mg/ml. An ACE inhibitory peptide was purified from FBMS using Sephadex G-75 gel chromatography, SP-Sephadex C-25 ion exchange chromatography and reversed-phase high-performance liquid chromatography on a C(18) column. The IC(50) value of purified ACE inhibitory peptide was 19.34 microg/ml, and 10 amino acid residues of the N-terminal sequence was EVMAGNLYPG. The purified peptide was evaluated for antihypertensive effect in spontaneously hypertensive rats (SHR) following oral administration. Blood pressure significantly decreased after peptide ingestion. This result suggested that FBMS may have beneficial effects on hypertension.