Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Bonito Bowels Autolysate

Six angiotensin I-converting enzyme inhibitory peptides were isolated from a bonito bowels autolysate. Their amino acids were sequenced as Tyr-Arg-Pro-Tyr, Gly-His-Phe, Val-Arg-Pro, Ile-Lys-Pro, Leu-Arg-Pro, and Ile-Arg-Pro. Peptides having corresponding amino acid sequences were synthesized by a solid-phase method and their inhibition of the activity measured. IC₅₀ of these peptides were estimated to be 320, 1100, 2.2, 2.5, 1.0, and 1.8 μM, respectively. The role of carboxyl terminal proline residues on the inhibition is discussed.     

Identification and Inhibitory Mechanism of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Bovine Hemoglobin

Angiotensin I-converting enzyme (ACE, EC.3.4.15.1) inhibitory peptide is an efficacious therapy for hypertension. In this study, four dipeptides, TY, FD, FL and FG, were identified from the desalted fraction of bovine hemoglobin hydrolysate, obtained by in vitro simulated gastrointestinal digestion, via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The IC₅₀ value of TY and FL are 96.43?±?6.17 and 290.66?±?57.92 μM, respectively. The result of molecular docking indicated that TY occupied the ACE subsite S1 and S1′ with a lowest estimated binding energy of ?9.96 Kcal/mol, while FL occupied the subsite S5 with a lowest estimated binding energy of ?9.37 Kcal/mol. The subsite S1′ and S2′ are closer to the ACE active center (Zn²⁺) than S5, and the lowest estimated binding energy of TY is lower than that of FL. This work provided new ACE-inhibitory peptides derived from bovine hemoglobin hydrolysate and explained their inhibitory mechanism.     

Peptidomic Analysis of ACE Inhibitory Peptides Extracted from Fermented Goat Milk

Angiotensin converting enzyme (ACE) is considered as main causative agent in growing hypertension and other cardiovascular disorders. Inhibition of ACE by producing and purifying bioactive peptides of fermented goat milk is aimed in this study. Protein extracted from goat milk was hydrolyzed with proteolytic enzymes of LH (Lactobacillus helveticus-cicc22171). ACE inhibitory peptides were purified from fermented samples of goat milk protein by optimizing incubation time to 8 h (S-8), 16 h (S-16), 24 h (S-24) and 36 h (S-36), via ultrafiltration. S-8 was used as control to compare the ACE inhibition trend. Molecular weight cut-off; 10000 Da (PM-10) and Ultracel 3K membrane was used to perform ultrafiltration. Sample with 24 h incubation time was considered as best hydrolyzed as compared to others, by applying Nin-Hydrin reaction and SDS-PAGE analysis. ACE inhibitory assay validated the authenticity of S-24 in inhibiting ACE, in vitro. Furthermore, Q executive hybrid quadrupole-orbitrap mass spectrometry was used to determine molecular structure and amino acid sequence of ACE inhibitory peptides. Three peptides, VLPVPQKAVPQ, VLPVPQKVVPQ and TQTPVVVPPFLQPEIMGVPKVKE containing functional amino acid structure, has been identified with highest ACE inhibitory activity on the basis of intensity, size and higher concentration of hydrophobic amino acids as shown in figure as graphical abstract. Fermented goat milk containing these novel bioactive peptides, can be used as nutraceuticals to inhibit ACE and control hypertension in future.

Graphical Abstract

     

In Vitro and In Silico Analysis of Novel ACE-Inhibitory Bioactive Peptides Derived from Fermented Goat Milk

In the study, two Lactobacillus cultures i.e. L. casei (NK9) and L. fermentum (LF) were studied for their proteolytic activity, di and tripeptidase activity, ACE-inhibitory activity and peptides production under optimized growth condition from fermented goat milk (Capra aegagrus hircus). NK9 and LF were found to be a strong proteolytic culture with 2.0% rate of inoculation after 48 h. LF (10 kDa retentate) produced maximum peptides among all the retentates of the fermented goat milk. Goat milk fermented with NK9 (10 kDa permeates) exhibited peptide sequence i.e. AFPEHK which had ACE inhibitory activity, matched with goat milk protein databases of AHTPDB. However, L. casei (NK9) and L. fermentum (LF) could be explored for the production of ACE inhibitory peptides from fermented goat milk.     

Activity Prediction and Molecular Mechanism of Bovine Blood Derived Angiotensin I-Converting Enzyme Inhibitory Peptides

Development of angiotensin I-converting enzyme (ACE, EC 3.4.15.1) inhibitory peptides from food protein is under extensive research as alternative for the prevention of hypertension. However, it is difficult to identify peptides released from food sources. To accelerate the progress of peptide identification, a three layer back propagation neural network model was established to predict the ACE-inhibitory activity of pentapeptides derived from bovine hemoglobin by simulated enzyme digestion. The pentapeptide WTQRF has the best predicted value with experimental IC₅₀ 23.93 μM. The potential molecular mechanism of the WTQRF / ACE interaction was investigated by flexible docking.     

In Silico Evaluation of Food Derived Bioactive Peptides as Inhibitors of Angiotensin Converting Enzyme (ACE)

International Journal of Peptide Research and Therapeutics - Hypertension is declared as the major risk factor of cardiovascular diseases and stroke, and the leading cause of premature deaths. ACE...     

Novel Angiotensin I-Converting Enzyme Inhibitory Peptides Found in a Thermolysin-Treated Elastin with Antihypertensive Activity

Angiotensin I-converting enzyme (ACE) inhibitory activity was generated from elastin and collagen by hydrolyzing with thermolysin. The IC₅₀ value of 531.6 µg/mL for ACE inhibition by the elastin hydrolysate was five times less than 2885.1 µg/mL by the collagen hydrolysate. We confirmed the antihypertensive activity of the elastin hydrolysate in vivo by feeding spontaneously hypertensive rats (male) on a diet containing 1% of the elastin hydrolysate for 9 weeks. About 4 week later, the systolic blood pressure of the rats in the elastin hydrolysate group had become significantly lower than that of the control group. We identified novel ACE inhibitory peptides, VGHyp, VVPG and VYPGG, in the elastin hydrolysate by using a protein sequencer and quadrupole linear ion trap (QIT)-LC/MS/MS. VYPGG had the highest IC₅₀ value of 244 µM against ACE and may have potential use as a functional food.     

Correction to: In Silico Evaluation of Food Derived Bioactive Peptides as Inhibitors of Angiotensin Converting Enzyme (ACE)

International Journal of Peptide Research and Therapeutics - The original version of the article unfortunately contained a typo in co-author name.     

Casein-Derived Peptides with Antihypertensive Potential: Production,Identification and Assessment of Complex Formation with Angiotensin I-Converting Enzyme (ACE) through Molecular Docking Studies

Hypertension is nowadays one of the major world concerns in public health. Several food proteins, among which caseins, can be substrates for generating peptides with antihypertensive potential. With the increasingly evolution of computational tools, in silico molecular modeling have gained prominence in studies of protein-ligand complexes in different research fields, such as pharmaceutics and biochemical engineering. However, the application of such methodologies in food-related research can be considered still embryonic. Thus, the central aim of the present work was to apply molecular modelling in order to elucidate the molecular bases of the anti-hypertensive potential of milk caseins-derived peptides. Firstly, hydrolysates obtained from a controlled trypsinolysis of caseins were fractioned according to their molecular weight, by ultrafiltration and RP-HPLC. The obtained fractions were evaluated with regard to their in vitro inhibitory angiotensin-converting enzyme activity (%I_ACE). Six chromatographic fractions were identified, and three of them displayed high ACE-inhibition (F₁: 80.68%; F₂: 79.00%; and F₄: 62.44%). Finally, intermolecular interactions networks in complexes formed between ACE and the identified peptides were assessed through in silico molecular docking. At the molecular level, a correlation between in vitro and in silico results was found: the peptides FFVAPFPEVFGK (F₆), FALPQYLK (F₂, F₄) and ALNEINQFYQK (F₁) presented the lowest biding energies and interacted by specific H-bonds, electrostatic and hydrophobic interactions formed within ACE active site S1 residues (Ala354, Glu384, and Tyr 523) and the Zn²⁺ coordinated residues (His383, His387, and Glu411). The fraction F₃, despite its low total peptide concentration, presented a moderate inhibitory activity for ACE (49.2%), likely due to H-bonds between HQGLPQEVLNENLLR and the active site S1 residues.

     

Antihypertensive Effect of Angiotensin I-Converting Enzyme Inhibitory Peptides from a Sesame Protein Hydrolysate in Spontaneously Hypertensive Rats

Sesame peptide powder (SPP) exhibited angiotensin I-converting enzyme (ACE) inhibitory activity, and significantly and temporarily decreased the systolic blood pressure (SBP) in spontaneously hypertensive rats (SHRs) by a single administration (1 and 10 mg/kg). Six peptide ACE inhibitors were isolated and identified from SPP. The representative peptides, Leu-Val-Tyr, Leu-Gln-Pro and Leu-Lys-Tyr, could competitively inhibit ACE activity at respective Ki values of 0.92 μM, 0.50 μM, and 0.48 μM. A reconstituted sesame peptide mixture of Leu-Ser-Ala, Leu-Gln-Pro, Leu-Lys-Tyr, Ile-Val-Tyr, Val-Ile-Tyr, Leu-Val-Tyr, and Met-Leu-Pro-Ala-Tyr according to their content ratio in SPP showed a strong antihypertensive effect on SHR at doses of 3.63 and 36.3 μg/kg, which accounted for more than 70% of the corresponding dosage for the SPP-induced hypotensive effect. Repeated oral administration of SPP also lowered both SBP and the aortic ACE activity in SHR. These results demonstrate that SPP would be a beneficial ingredient for preventing and providing therapy against hypertension and its related diseases.     

Effects of Angiotensin I-Converting Enzyme Inhibitory Substances Derived from Indonesian Dried-salted fish on Blood Pressure of Rats

Indonesian dried-salted fish (DSF) was produced from skipjack tuna by soaking the flesh in 15% NaCl (DSF I) or 25% NaCl (DSF II). The DSFs were then hydrolyzed by trypsin, chymotrypsin, Pronase E, and pepsin. Angiotensin I-converting enzyme (ACE) inhibitory activity was measured. The pepsin digest showed the highest inhibitory activity (IC₅₀; 0.63 mg protein/ml). DSF II hydrolysate had higher inhibitory activity than that in DSF I. A three-month storage period of DSF gave higher ACE-inhibitory activity than that of 6 months. An oral administration of pepsin hydrolysate significantly decreased the blood pressure of rats. From the purification steps, at least 4 inhibitor peptides were found. The amino acid sequences of the peptides were Val-Ala-Trp-Lys-Leu, Trp-Ser-Lys-Val-Val-Leu, Ser-Lys-Val-Pro-Pro, and Cys-Trp-Leu-Pro-Val-Tyr, with an IC₅₀ value of 31.97, 156.28, 74.22, and 22.20 μM, respectively.     

<Emphasis Type="Italic">In Silico</Emphasis> and <Emphasis Type="Italic">In vitro</Emphasis> Analysis of Novel Angiotensin I-Converting Enzyme (ACE) inhibitory Bioactive Peptides Derived from Fermented Camel Milk (<Emphasis Type="Italic">Camelus dromedarius</Emphasis>)

In this study, Lactobacillus bulgaricus NCDC (09) and Lactobacillus fermentum TDS030603 (LBF) were evaluated for their ACE-inhibitory activity and peptides production under optimized conditions from fermented camel milk (Camelus dromedarius). Lactic cultures were evaluated for their pepX activity, proteolytic activity and ACE-inhibitory activity. 09 culture exhibited higher PepX and ACE-inhibitory activity than LBF. 2% rate of inoculation and 12 h of incubation were optimized on the basis of pepX and proteolytic activity. Purified peptides from fermented camel milk were characterized by amino acids profiling through the search in BlastP, Protein information resource (PIR) databases. ACE-inhibitory activity of different peptides from fermented camel milk were also confirmed by the database of antihypertensive peptides (AHTPDB). Fermented camel milk produced by Lactobacillus cultures could be a novel source of ACE-inhibitory peptides.     

血管紧张素转化酶抑制肽的研究进展

血管紧张素转化酶 (angiotensin I convertingenzyme ,ACE)在血压调节方面起着重要的作用 ,当其受到抑制时血压就会降低。许多合成的ACE抑制剂被广泛地应用于临床 ,但会造成多种副作用。近年来 ,对天然ACE抑制肽的研究表明 ,一些来源于蛋白酶解产生的活性肽可以对ACE起到有效的抑制作用。综述了血管紧张素转化酶的抑制肽的降压原理 ,种类和来源以及结构特点等的研究进展 ,并对其应用前景进行了展望。     

食品蛋白质中血管紧张素转化酶抑制肽的研究

血管紧张素转化酶Ⅰ (angiotensinIconvertingenzyme ,简称ACE)在人体血压调节过程中起重要的生理作用。源于食品蛋白质中的血管紧张素转化酶抑制肽 (angiotensinIconvertingenzymeinhibitorypeptides ,简称ACEIP)有明显的降血压作用 ,这些肽是通过抑制ACE的活性起降血压作用。文章中综述了来源于各种食品蛋白质的ACEIP的最新研究进展以及两种主要制备方法和评价方法 ,并对食品蛋白质中ACEIP的应用前景进行了展望     

Influence of Whey Protein Concentrate on the Production of Antibacterial Peptides Derived from Fermented Milk by Lactic Acid Bacteria

In the study, growth, proteolysis and antimicrobial activity of lactic acid bacteria were evaluated in skim milk medium supplemented with different concentration of whey protein concentrate (WPC 70). Lactobacillus helveticus (V3) showed maximum pH reduction with 1% WPC. Lactobacillus rhamnosus (NS4) also produced maximum lactic acid production and viable cells counts at 1 and 1.5% WPC, respectively. However, V3 showed maximum proteolytic activity with 1.5% WPC. Streptococcus thermophilus (MD2) was found to exhibit maximum antimicrobial activity with 1.5% WPC. Peptides formed during fermentation were purified by RP-HPLC and identified using RP-LC/MS analysis. Antimicrobial peptide was identified as lactoferrin, which was found in fermented milk supplemented with 1.5% WPC by NS4.     

Search for potential Angiotensin Converting Enzyme (ACE)-inhibitors from plants

MeOH extracts, fractions and pure substances from Musanga cecropioides, Cecropia species and Crataegus oxyacantha /C. monogyna were screened by using an in vitro bio-assay based on the inhibition of Angiotensin Converting Enzyme (ACE), as measured from the enzymatic cleavage of the chromophore-fluorophore-labelled substrate dansyltriglycine into dansylglycine and diglycine. Phenolic acids showed no significant ACE-inhibition whereas flavonoids and proanthocyanidins demonstrated inhibitory activity at 0.33 mg/ml using this test system.     

First Report of Screening of Novel Angiotensin-I Converting Enzyme Inhibitory Peptides Derived from the Red Alga Acrochaetium sp.

Marine Biotechnology - ACE inhibitors generated from food proteins have recently become the most well-known subclass of bioactive peptides, and their bio-functionality can be a potential...