Enzyme Inhibitory Peptides Research Articles

Molecular docking and antihypertensive effects of a novel angiotensin-I converting enzyme inhibitory peptide from yak bone.

A novel angiotensin-converting enzyme (ACE) inhibitory peptide ser-ala-ser-val-ile-pro-val-ser-ala-val-arg-ala (SASVIPVSAVRA) was purified and identified from yak bone by Electrospray Ionization-Time of Flight-Mass Spectrometry (ESI-TOF-MS). Results in vitro showed that the peptide exhibited strong ACE inhibition activities with an IC50 of 54.22 μM. Molecular docking results showed the binding between the peptide SASVIPVSAVRA and ACE mainly driven by van der Waals forces, hydrogen bonds and metal receptor. Interestingly, the ACE inhibition activities of the peptide increased about 19% after digestion, but none of its metabolites showed stronger activity than it. The in vivo experiment showed that the antihypertensive effect of peptide SASVIPVSAVRA at dose of 30 mg/kg is nearly equal to Captopril at dose of 10 mg/kg to spontaneously hypertensive rats (SHRs). The antihypertensive effect mechanism of SASVIPVSAVRA should be further studied through plasma metabolomics and bioanalysis. Structure analysis of amino acids and peptides produced during digestion may help better understand the antihypertensive effect of peptides.

Improving ACE inhibitory activity of hazelnut peptide modified by plastein: Physicochemical properties and action mechanism

The plastein reaction can increase the activity of angiotensin-converting enzyme (ACE) inhibitory peptides, but the underlying mechanism is unknown. Hence, hazelnut protein hydrolysate and hazelnut peptide YLVR were used as substrate to explore the effect of plastein on physicochemical properties and the mechanism of structural change. The increase in turbidity and particle size and the decrease in free amino groups indicated that the reaction occurred via condensation. The modified products of YLVR were identified by NANO-HPLC-MS/MS, indicating that the N-terminal homologous amino acid aggregates in the plastein. Novel ACE inhibitory peptide YYLVR, YLLVR, and YYLLVR were synthesized and their inhibition rates were 66.35, 72.61, and 89.10 %, respectively, which were higher than that of YLVR (52.58 %). MD simulation showed that YYLLVR exhibited the lowest binding energies of −35.98 ± 2.30 kcal/mol to ACE. Taken together, plastein reaction is a promising strategy for inducing structural modifications to improve the activity of peptide.

The addition of probiotic promotes the release of ACE-I peptide of Cheddar cheese: Peptide profile and molecular docking

The use of probiotics to promote the release of bioactive peptides during Cheddar cheese ripening was investigated. The proteolytic and angiotensin-converting enzyme inhibitory (ACE-I) activities and ACE-I peptide profile of Cheddar cheese with different probiotics were analysed and compared. Molecular docking was used to analyse the binding site of peptide to ACE molecule. Compared with other cheeses, ACE-I activity of Lactobacillus helveticus cheese was the highest (79.71%), and the degree of proteolysis was higher and the molecular mass was lower. Most of the peptides were less than 1.6 kDa. In addition, 43.31–51.59% of the peptides in cheese originated from β-casein, mainly from the degradation of starter and probiotics. SKVLPQ and YQEPVLGP, which were uniquely identified in L.helveticus cheese, could interact with the S1 and S2 active pocket of ACE, respectively. Especially, YQEPVLGP could bind to ACE at multiple sites and was an efficient ACE inhibitory peptide.

Identification, in silico screening, and molecular docking of novel ACE inhibitory peptides isolated from the edible symbiot Boletus griseus-Hypomyces chrysospermus

The aim of this study is to find angiotensin-Ⅰ-converting enzyme inhibitory (ACEI) peptides from the edible symbiot Boletus griseus-Hypomyces chrysospermus (BGHC). The peptides from the methanol extract of BGHC were identified through ultraperformance liquid chromatography quadrupole Orbitrap tandem mass spectrometry analysis coupled with de novo sequencing by using Peak Studio software. Subsequently, two ACEI peptides, being KYPHVF and LFRPE, were screened on the basis of PeptideRanker and the AHTpin online server. The in silico absorption, distribution, metabolism, excretion and toxicities (ADMET) of the two peptides were predicted with AdmetSAR software, and the two peptides showed good absorption and nontoxicity. Meanwhile, the ACEI mechanism of KYPHVF and LFRPE was analyzed through molecular docking with SYBYL-X 2.0 software. The molecular docking study revealed that the total scores of the interactions of KYPHVF and LFRPE with ACE were 12.53 and 11.34, respectively. KYPHVF and LFRPE could establish hydrogen bonds and hydrophobic interactions with the active site of ACE. Furthermore, the ACEI activities of KYPHVF and LFRPE were determined in vitro with the IC50 values of 5.99 and 58.15 μmol/L, respectively.

Novel angiotensin I-converting enzyme (ACE) inhibitory peptides from walnut protein isolate: Separation, identification and molecular docking study.

Walnut protein isolate was hydrolyzed using alcalase® to obtain angiotensin-I-converting enzyme (ACE) inhibitory (ACEI) peptides. The components with high ACEI activity were successfully purified from walnut protein isolate hydrolysates (WPIH) by ultrafiltration and G-25 gel chromatography. The 1520 peptides were identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Then the screening model of ACEI peptides was established by in silico approach. It was found that four ACEI active peptides (PPKP, YPQY, YLPP, and PKPP) were obtained with IC50 values ranging from 506 to 89 μmol/L, among which PPKP had the highest ACEI activity (IC50 =89 ± 1μmol/L). The four peptides mentioned above were novel, non-toxic, and resistant to gastrointestinal digestion. The molecular docking studies showed that the ACEI effect of ACEI peptide was mainly due to the interaction with residues of Gln281 and His353 in the ACE active pockets. In vivo availability of ACEI peptides showed that the probability of PPKP binding to ACE was 37.9% in the human body. Our studies suggest that the ACEI peptides derived from the WPIH can be considered functional foods that can prevent hypertension. PRACTICAL APPLICATIONS: Hypertension is a significant risk factor for cardiovascular and cerebrovascular disease, the leading cause of death worldwide. This study used a cost-effective method to isolate and identify potential ACEI peptides from the walnut meal. Since the walnut meal is often discarded in the processing of walnut products and thus pollutes the environment, the preparation of walnut meal into ACEI peptides can reduce the impact of hypertension on people and reduce environmental pollution. The experimental results show that walnut ACEI peptides are a safe and healthy nutritional product.

Identification, molecular docking, and kinetic studies of six novel angiotensin-I-converting enzyme (ACE) inhibitory peptides derived from Kenaf (Hibiscus cannabinus L.) seed

Kenaf (Hibiscus cannabinus L.) seed is a valuable protein source that could be used to prepare protein hydrolysates with antihypertensive properties. However, the potential of using kenaf seeds for health food and pharmaceutical applications has not been fully exploited. Thus, the aim of this study was to identify and characterise the Angiotensin-I-Converting Enzyme (ACE) inhibitory peptides derived from the optimized hydrolysis conditions of kenaf seed protein hydrolysates (KSPH). The optimum hydrolysis conditions determined by response surface methodology (RSM) were as follows: temperature 65 °C, pH 6.5, hydrolysis time 2.25 h, and enzyme/substrate (E/S) ratio of 0.03 (w/w). Under these conditions, the degree of hydrolysis (DH) was 55.28 % and ACE inhibitory activity was 75.51 %. Also, the low molecular weight peptide fractions, <2 kilodalton (kDa) and 2–5 kDa showed the highest ACE-inhibitory activity (82.27 % and 83.69 %, respectively). The 2–5 kDa fraction by Quadrupole-Time-of-Flight Liquid Chromatography-Mass Spectrometry (QTOF LC − MS) revealed the abundance of six peptides, LYWSYLYN, ALFYWVS, LLLHAL, AKSCVVFP, INPPSTTN, and WTIPTPS. Kinetic studies showed that peptide LYWSYLYN possessed the highest Michaelis constant (Km), maximum velocity (Vmax) values and the lowest inhibitor constant (Ki) values, suggesting of its superior ACE inhibitory activity compared to other peptides.

Purification and identification of antioxidant and angiotensin converting enzyme-inhibitory peptides from Guangdong glutinous rice wine

Guangdong glutinous rice wine, a type of Chinese yellow rice wine, is rich in a variety of bioactive peptides. In this study, polypeptides with antioxidant and angiotensin converting enzyme (ACE)-inhibitory activities were isolated from Guangdong glutinous rice wine, and their activities and molecular mechanisms were studied. The peptide fraction (F2-2), which exhibited the strongest antioxidant and ACE inhibitory activities, was separated by ultrafiltration and RP-HPLC. A total of 76 peptides were identified by LC-MS/MS, and four peptides with potential antioxidant activities were obtained: VLSGA (445.2536 Da), VISGA (445.2536 Da), MGKAA (476.2417 Da) and GHVAA (453.2336 Da). These four peptides showed significant antioxidant activity with EC50 values of 0.118 mg/mL, 0.056 mg/mL, 0.054 mg/mL and 0.027 mg/mL respectively, and effectively protected cells against oxidative damage. Molecular docking showed that all these four peptides could interact with key active sites on the receptor proteins CD38 and Keap1. Furthermore, these peptides showed good safety and stability according to in silico prediction.

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

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 alternative to natural bioactive food components and synthetic drugs. The bioactivities of Acrochaetium sp., the red alga used in this investigation, have never been reported before. Screening of bioactive peptides from Acrochaetium sp. as ACE inhibitors were hydrolyzed with various proteolytic enzymes. Protein hydrolysates were fractionated separately using reversed phased (RP) and strong cation exchange (SCX) chromatography and identified as VGGSDLQAL (VL-9) using α-chymotrypsin. It comes from Phycoerythrin (PE), an abundant protein in a primarily red alga. The peptide VL-9 shows the ACE inhibitory activity with IC50 value 433.1 ± 1.08µM. The inhibition pattern showed VL-9 as a non-competitive inhibitor. Molecular docking simulation proved that VL-9 was non-competitive inhibition due to the interaction peptide and ACE was not in the catalytic site. Moreover, VL-9 derived from Acrochaetium sp. is a natural bioactive peptide that is safer and available for food protein; also, the ACE inhibitory peptide derived from Acrochaetium sp. could be the one alternative resource to develop functional food for combating hypertension.

Purification identification and function analysis of ACE inhibitory peptide from Ulva prolifera protein

In the present study, Ulva prolifera, an edible alga, was used to prepare angiotensin-I converting enzyme (ACE) inhibitory peptide. The algae protein was isolated and later hydrolyzed by five commercial enzymes (alcalase, papain, pepsin, trypsin, neutral protease), either individually or in combination. Hydrolysate, with the highest in vitro ACE inhibitory activity, was processed using the Sephadex-G100, ultrafiltration, HPLC-Q-TOF-MS, ADMET screening and molecular docking, respectively. The ACE inhibitory peptide DIGGL with a IC50 value of 10.32 ± 0.96 μM was then identified. The peptide against ACE by a non-competitive mode and mainly attributable to the three Conventional Hydrogen Bonds. It could activate Endothelial nitric oxide synthase activity in NO generation and reduce Endothelin-1 secretion induced by Angiotensin II in Human umbilical vein endothelial cells. Meanwhile, DIGGL could promote mice splenocytes proliferation, which was also effective when co-incubated with Con A or LPS, respectively. Besides, the anti-ACE peptide could remain active during the digestion of gastrointestinal proteases (pepsin-trypsin) in vitro.

A novel angiotensin-I-converting enzyme inhibitory peptide from oyster: Simulated gastro-intestinal digestion, molecular docking, inhibition kinetics and antihypertensive effects in rats.

In this study, a novel peptide, AEYLCEAC with high angiotensin-I-converting enzyme inhibitory (ACEI) activity was screened from oyster (Crassostrea gigas) hydrolysates, which was obtained from simulated gastro-intestinal digestion. Candidate peptides were confirmed to have a higher binding to angiotensin-I-converting enzyme (ACE) than the positive drug phosphoinic tripeptide calculated by Discovery Studio, and AEYLCEAC showed the highest ACE inhibition rate in vitro with a IC50 of 4.287 mM. Lineweaver-Burk plots confirmed that the peptidic inhibitory type of ACE is competitive. The molecular docking showed that ACEI activity of the AEYLCEAC was mainly due to the hydrogen bonding interactions with the active pockets (S1 and S2) of ACE. In vivo, AEYLCEAC effectively reduced diastolic blood pressure (DBP) and Systolic blood pressure (SBP) in hypertensive rats. These results indicate that AEYLCEAC might act as a helpful ingredient in functional foods or pharmaceuticals for the prevention and treatment of hypertension.

Peptides inhibiting angiotensin-I-converting enzyme: Isolation from flavourzyme hydrolysate of Protaetia brevitarsis larva protein and identification

Many angiotensin-I-converting enzyme (ACE) inhibitory peptides are used to prevent and manage hypertension. In this study, ACE inhibitory peptides were isolated from an insect protein that is attracting attention for it potential antihypertensive activity. Protaetia brevitarsis larva protein was enzymatically hydrolyzed by Flavourzyme®, and the hydrolysate was shown to inhibit ACE. Subsequent fractionation, using ultrafiltration and gel permeation chromatography followed by liquid chromatography-tandem mass spectrometry analysis, identified four previously unknown peptides with significant ACE inhibition characteristics (Ser-Tyr, Pro-Phe, Tyr-Pro-Tyr, and Trp-Ile). The highest inhibition activity observed for Trp-Ile. These peptides stimulated production of NO in human umbilical vein endothelial cells and, based on molecular docking analysis, exerted their inhibitory effects via hydrogen bonding with the ACE receptor active site. Thus, the identified peptides can be considered as promising candidates for ACE inhibition and have potential to be used as functional food ingredients.

Valorization of coffee industry wastes: Comprehensive physicochemical characterization of coffee silverskin and multipurpose recycling applications

Every year, the coffee supply chain produces tons of waste materials from the processing of the coffee bean. Coffee silverskin (CS) is the only waste product from the coffee bean roasting phases but as roasting is a key step in obtaining the coffee beverage, there are tons of CS collected and thrown away by coffee roasting industries. This study is based on the characterization of this integument, with a view to its use in nutritional, nutraceutical and industrial fields. From the results obtained, silverskin can be used in the food sector for its nutritional profile with a good amount of protein (18.9%) and total dietary fiber (34.7%) andits low-fat content (3.0%). Food safety was also determined by evaluating the low levels of contaminants such as ochratoxin A (OTA) and acrylamide (AA), with values < 0.1 mg/kg and <0.02 mg/kg respectively. Low concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs) completed the safety-related overview in terms of CS contamination. For the nutraceutical aspect, an in-silico analysis of the peptide fraction was proper to evaluate the presence of angiotensin-converting enzyme (ACE) inhibitory peptides, antioxidants and dipeptidyl peptidase (DPP) IV inhibitors with promising uses for the treatment of diabetes and its side effects. Finally, through morphological-structural characterization of CS, the main constituents such as lignin, cellulose and hemicellulose were identified spectrally by Fourier transform infrared spectroscopy (FT-IR) and solid-state CP/MAS 13C NMR spectroscopy. The CS thermostability was monitored by thermogravimetric (TG) analysis, and the tegument surface was evaluated by Scanning Electron Microscopy (SEM) and volumetric nitrogen adsorption analysis. This information provides a broader view of the possible uses of CS as a filler for biocomposite materials. Therefore, from the perspective of recovering waste materials from food supply chains, coffee silverskin could be a good product to focus on.

Bioinformatics identification and molecular mechanism of angiotensin-converting enzyme and dipeptidyl peptidase-IV inhibitory peptides from in silico digest of Crassostrea gigas

Bioinformatics identification and molecular mechanism of angiotensin-converting enzyme and dipeptidyl peptidase-IV inhibitory peptides from in silico digest of Crassostrea gigas

Isolation and identification of novel angiotensin I-converting enzyme (ACE) inhibitory peptides from Pony Seed and evaluation of the inhibitory mechanisms

In this work, four novel angiotensin I-converting enzyme inhibitory (ACEI) peptides were isolated and identified from peony (Paeonia suffruticosa Andr.) seed hydrolysate (PSH) by consecutive chromatography and UPLC-ESI-QTOF-MS/MS. The IC50 values of HWS (0.640 ±0.016 mg/mL) and VLSGF (0.328 ± 0.040 mg/mL) were significantly (p < 0.05) lower than those of the other two peptides. The Lineweaver-Burk plots showed that VLSGF is competitive inhibition against ACE and HWS acted as a mixed-type inhibitor. Meanwhile, the results of molecular docking showed hydrogen interactions between VLSGF/HWS and ACE. In human endothelial cells, the pretreatments of VLSGF and HWS could increase the production of nitric oxide (NO) and the expression of endothelial nitric oxide synthase (eNOS). In addition, they also decreased the reactive oxygen species (ROS) production. These results indicated that it may be possible to use peony seed protein hydrolysate to create ingredients for functional foods.

Isolation, identification, molecular docking analysis, and cytoprotection of seven novel angiotensin I-converting enzyme inhibitory peptides from miiuy croaker byproducts-swim bladders

For efficiently utilizing the processing byproducts of miiuy croaker to prepare novel angiotensin I-converting enzyme (ACE) inhibitory (ACEi) peptides, in vitro gastrointestinal (GI) digestion method was screened and employed to prepare swim bladder hydrolysate with the highest ACEi activity. Subsequently, seven novel ACEi peptides were isolated from the hydrolysate and identified as DEGPE, EVGIQ, SHGEY, GPWGPA, GPFGTD, SPYGF, and VIGPF with molecular weights of 545.49, 544.58, 591.55, 583.63, 592.59, 569.60, and 531.63 Da, respectively. SHGEY and SPYGF exhibited remarkable ACEi activity with IC50 values of 0.86 ± 0.12 and 0.37 ± 0.06 mg/mL. Molecular docking experiment illustrated that the significant ACEi activity of SHGEY and SPYGF with the affinity of -8.7 and -9.7 kcal/mol mainly attributed to effectively combining with the ACEi active sites by hydrophobic interaction, electrostatic force and hydrogen bonding. Moreover, SHGEY and SPYGF could significantly up-regulate the nitric oxide (NO) production and decrease the endothelin-1 (ET-1) secretion in human umbilical vein endothelial cells (HUVECs), but also abolished the negative impacting of norepinephrine to the levels of NO and ET-1. Furthermore, SHGEY and SPYGF showed significant protection to HUVECs against H2O2 damage by increasing superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity to lower the contents of reactive oxide species and malondialdehyde. Consequently, ACEi peptides derived from miiuy croaker swim bladders, especially SHGEY and SPYGF, are health-promoting ingredients for functional products as a supplementary treatment to hypertension and cardiovascular diseases.

Formation and inhibition mechanism of novel angiotensin I converting enzyme inhibitory peptides from Chouguiyu

Angiotensin I converting enzyme (ACE) inhibitory peptides from fermented foods exhibit great potential to alleviate hypertension. In this study, the peptide extract from Chouguiyu exhibited a good inhibition effect on ACE, and the inhibition rate was significantly enhanced after fermentation for 8 days. The ACE inhibitory peptides were further identified, followed by their inhibition and formation mechanisms using microbiome technology and molecular docking. A total of 356 ACE inhibitory peptides were predicted using in silico, and most ACE inhibitory peptides increased after fermentation. These peptides could be hydrolyzed from 94 kinds of precursor proteins, mainly including muscle-type creatine kinase, nebulin, and troponin I. P1 (VEIINARA), P2 (FAVMVKG), P4 (EITWSDDKK), P7 (DFDDIQK), P8 (IGDDPKF), P9 (INDDPKIL), and P10 (GVDNPGHPFI) were selected as the core ACE inhibitory peptides according to their abundance and docking energy. The salt bridge and conventional hydrogen bond connecting unsaturated oxygen atoms in the peptides contributed most to the ACE inhibition. The cleavage proteases from the microbial genera in Chouguiyu for preparing these 7 core ACE inhibitory peptides were further analyzed by hydrolysis prediction and Pearson's correlation. The correlation network showed that P7, P8, and P9 were mainly produced by the proteases from LAB including Lactococcus, Enterococcus, Vagococcus, Peptostreptococcus, and Streptococcus, while P1, P2, P4, and P10 were mainly Produced by Aeromonas, Bacillus, Escherichia, and Psychrobacter. This study is helpful in isolating the proteases and microbial strains to directionally produce the responding ACE inhibitory peptides.

Novel angiotensin-converting enzyme inhibitory peptides from tuna byproducts-milts: Preparation, characterization, molecular docking study, and antioxidant function on H2O2-damaged human umbilical vein endothelial cells.

To prepare peptides with high angiotensin-converting enzyme (ACE) inhibitory (ACEi) activity, Alcalase was screened from five proteases and employed to prepare protein hydrolysate (TMH) of skipjack tuna (Katsuwonus pelamis) milts. Subsequently, 10 novel ACEi peptides were isolated from the high-ACEi activity TMH and identified as Tyr-Asp-Asp (YDD), Thr-Arg-Glu (TRE), Arg-Asp-Tyr (RDY), Thr-Glu-Arg-Met (TERM), Asp-Arg-Arg-Tyr-Gly (DRRYG), Ile-Cys-Tyr (ICY), Leu-Ser-Phe-Arg (LSFR), Gly-Val-Arg-Phe (GVRF), Lys-Leu-Tyr-Ala-Leu-Phe (KLYALF), and Ile-Tyr-Ser-Pro (IYSP) with molecular weights of 411.35, 404.41, 452.45, 535.60, 665.69, 397.48, 521.61, 477.55, 753.91, and 478.53 Da, respectively. Among them, the IC50 values of ICY, LSFR, and IYSP on ACE were 0.48, 0.59, and 0.76 mg/mL, respectively. The significant ACEi activity of ICY, LSFR, and IYSP with affinities of −7.0, −8.5, and −8.3 kcal/mol mainly attributed to effectively combining with the ACEi active sites through hydrogen bonding, electrostatic force, and hydrophobic interaction. Moreover, ICY, LSFR, and IYSP could positively influence the production of nitric oxide (NO) and endothelin-1 (ET-1) secretion in human umbilical vein endothelial cells (HUVECs) and weaken the adverse impact of norepinephrine (NE) on the production of NO and ET-1. In addition, ICY, LSFR, and IYSP could provide significant protection to HUVECs against H2O2 damage by increasing antioxidase levels to decrease the contents of reactive oxide species and malondialdehyde. Therefore, the ACEi peptides of ICY, LSFR, and IYSP are beneficial functional molecules for healthy foods against hypertension and cardiovascular diseases.

Structural requirements and interaction mechanisms of ACE inhibitory peptides: molecular simulation and thermodynamics studies on LAPYK and its modified peptides

The understanding of the structural requirements and the intermolecular-interaction mechanism are important for discovering potent angiotensin-converting enzyme (ACE) inhibitory peptides. In this study, we modified an egg-white derived peptide, LAPYK, using the amino acids with different properties to produce the LAPYK-modified peptides. The ACE inhibitory activities of the modified peptides were determined to explore the structural requirements of ACE inhibitory peptides (ACEIPs). Molecular simulation and isothermal titration calorimetry analysis were used to investigate interactions between the peptides and ACE. We found that hydrophobicity and the amino acids with ring structures were beneficial for the ACE inhibitory activities of the peptides. The results of the molecular mechanics poisson boltzmann surface area (MMPBSA) binding free energy calculations indicated that the polar solvation free energy (ΔGpolar) of the charged peptides (LAPYK, LAPYE) were unfavorable for binding to ACE. On the other hand, the results of isothermal titration calorimetry analyses suggested that the enthalpy-driven ACE-peptide interactions were more favorable than the entropy-driven ACE-peptide interaction counterparts.

Identification and characterization of a novel tetrapeptide from enzymatic hydrolysates of Baijiu byproduct

In order to prepare angiotensin I-converting enzyme (ACE) inhibitory peptides, distilled spent grains of Chinese strong-flavor Baijiu were hydrolyzed by alcalase followed by papain under optimized conditions. A superior ACE inhibitory peptide was separated and purified by ultrafiltration and high-performance liquid chromatography (HPLC), and its amino acid sequence was further identified as Gln-Gly-Val-Pro (QGVP) by electrospray mass spectrometry (ESI-MS). QGVP formed 6 hydrogen bonds with the active site of ACE, which is responsible for reducing α-helix structure content of ACE causing subsequent inactivation. Moreover, it showed no significant cytotoxicity toward human umbilical vein endothelial cells (HUVECs), and significantly induced phosphorylation of endothelial nitric oxide synthase (p-eNOS) and decreased endothelin 1 (END1) expression in angiotensin I (Ang I)-treated HUVECs, demonstrating the potential antihypertensive effect. The peptide QGVP hydrolyzed from distilled spent grain proteins of Chinese strong-flavor Baijiu was expected to be used as a food ingredient to prevent or co-treat hypertension with other chemical drugs.

Insights into in vitro digestion properties and peptide profiling of Chinese rubing PDO cheese prepared using different acidification technology

Rubing cheese is a traditional Chinese Protected Designation of Origin (PDO) cheese consumed for more than six hundred years, but to date, the digestion properties and peptide profiling during simulated gastrointestinal digestion are still uncertain. This study aimed to investigate the effects of traditional direct acidification technology (TRB) and fermentation acidification technology on digestion properties and peptide profiling of rubing cheese (FRB) proteins after simulated gastrointestinal digestion by protein digestomics, coupled with bioinformatic in silico analyses to identify potential bioactive peptides. The results demonstrated that FRB could significantly improve the in vitro digestibility, protein degradation, and polypeptide content than TRB (P ＜ 0.05). Furthermore, a total of 369 and 332 peptides were identified in FRB- and TRB-pancreatic digests, respectively, using LC-MS/MS. FRB could release more low molecular weight peptides of 400–1200 Da from α-casein and β-casein after digestion. These low peptides included 16 reported potential ACEIPs (angiotensin I-converting enzyme inhibitory peptides), 11 dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides, and 6 antioxidant peptides, while TRB contained more than the reported potential antimicrobial peptides (10). In vitro activity determination showed that FRB had significantly higher ACEI, α-glucosidase inhibitory, and antioxidant activities than TRB during the entire digestion time (P ＜ 0.05), which was correlated to the reported potential bioactive peptides released during the digestion of FRB. Our study is the most comprehensive protein digestomic analysis of Chinese rubing cheese to date and provides a new positive outlook on rubing cheese consumption.