As far as comorbidity is concerned, cardiovascular diseases (CVD) appear to be accounted for the highest prevalence, severity, and fatality among COVID 19 patients. A wide array of causal links connecting CVD and COVID-19 baffle the overall prognosis as well as the efficacy of the given therapeutic interventions. At the centre of this puzzle lies ACE2 that works as a receptor for the SARS-CoV-2, and functional expression of which is also needed to minimize vasoconstriction otherwise would lead to high blood pressure. Furthermore, SARS-CoV-2 infection seems to reduce the functional expression of ACE2. Given these circumstances, it might be advisable to consider a treatment plan for COVID-19 patients with CVD in an approach that would neither aggravate the vasodeleterious arm of the renin-angiotensinogen-aldosterone system (RAAS) nor compromise the vasoprotective arm of RAAS but is effective to minimize or if possible, inhibit the viral replication. Given the immune modulatory role of Zn in both CVD and COVID-19 pathogenesis, zinc supplement to the selective treatment plan for CVD and COVID-19 comorbid conditions, to be decided by the clinicians depending on the cardiovascular conditions of the patients, might greatly improve the therapeutic outcome. Notably, ACE2 is a zinc metalloenzyme and zinc is also known to inhibit viral replication.
SARS-CoV-2 has a zoonotic origin and was transmitted to humans via an undetermined intermediate host, leading to infections in humans and other mammals. To enter host cells, the viral spike protein (S-protein) binds to its receptor, ACE2, and is then processed by TMPRSS2. Whilst receptor binding contributes to the viral host range, S-protein:ACE2 complexes from other animals have not been investigated widely. To predict infection risks, we modelled S-protein:ACE2 complexes from 215 vertebrate species, calculated changes in the energy of the complex caused by mutations in each species, relative to human ACE2, and correlated these changes with COVID-19 infection data. We also analysed structural interactions to better understand the key residues contributing to affinity. We predict that mutations are more detrimental in ACE2 than TMPRSS2. Finally, we demonstrate phylogenetically that human SARS-CoV-2 strains have been isolated in animals. Our results suggest that SARS-CoV-2 can infect a broad range of mammals, but few fish, birds or reptiles. Susceptible animals could serve as reservoirs of the virus, necessitating careful ongoing animal management and surveillance.
Application of non-thermal treatment to proteins prior to enzymatic hydrolysis can facilitate the release of novel bioactive peptides (BPs) with unique biological activities. In this study, lupin protein isolate was pre-treated with ultrasound and hydrolysed using alcalase and flavourzyme to produce alcalase hydrolysate (ACT) and flavourzyme hydrolysate(FCT). These hydrolysates were fractionated into 1, 5, and 10 kDa molecular weight fractions using a membrane ultrafiltration technique. The in vitro angiotensin-converting enzyme (ACE) studies revealed that unfractionated ACT (IC50 = 3.21 mg mL-1) and FCT (IC50 = 3.32 mg mL-1) were more active inhibitors of ACE in comparison to their ultrafiltrated fractions with IC50 values ranging from 6.09 to 7.45 mg mL-1. Molecular docking analysis predicted three unique peptides from ACT (AIPPGIPY, SVPGCT, and QGAGG) and FCT (AIPINNPGKL, SGNQGP, and PPGIP) as potential ACE inhibitors. Thus, unique BPs with ACE inhibitory effects might be generated from ultrasonicated lupin protein.
Men show higher vulnerability to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (COVID-19) and present with depleted testosterone levels. Reports pertaining to high luteinizing hormone (LH), while diminished levels of in COVID-19 patients negate the hypothalamic-pituitary-testicular (HPT) axis mediated lowering of testosterone. Although not evidenced, high testicular expression of angiotensin-converting enzymes-2 (ACE2), that aids viral entry into cells, may suggest direct viral-testicular invasion. However, secondary inflammation and oxidative stress (OS), owing to SARS-CoV-2 infection, are more likely to impair steroidogenesis. Moreover, blockage of ACE2 aided angiotensin II into angiotensin (1-7) conversion may also affect testosterone synthesis. SARS-CoV-2, by mimicking adrenocorticotrophic (ACTH) hormones, may trigger host antibodies against the ACTH molecules to suppress host stress response. This commentary concisely presents the possible mechanisms by which SARS-CoV-2 infection may affect testosterone levels, which possibly result in compromised male reproductive health.
Discrepancies in angiotensin-1 converting enzyme (ACE) allele genetic susceptibility with disease etiology have been attributed to ethnic differences. We investigated ACE gene polymorphism of the multiethnic Malaysian population by utilizing nested polymerase chain reaction. Allelic frequency of 0.65 and 0.35 for I and D allele, respectively in the pooled population was comparable with other Asian populations. A significant association was found between the Malaysian ethnic groups and ACE I/D genotype. The II genotype was found at higher frequency among the Malays but a greater frequency of DD genotype among Indians.
Angiotensin-converting enzyme (ACE) regulates blood pressure and has been implicated in several conditions including lung injury, fibrosis and Alzheimer's disease. Medicinal mushroom Ganordema lucidum (Reishi) cystathionine beta-synthase (GlCBS) was previously reported to possess ACE inhibitory activities. However, the inhibitory mechanism of CBS protein remains unreported. Therefore, this study integrates in silico sequencing, structural and functional based-analysis, protein modelling, molecular docking and binding affinity calculation to elucidate the inhibitory mechanism of GlCBS and Lignosus rhinocerus (Tiger milk mushroom) CBS protein (LrCBS) towards ACE. In silico analysis indicates that CBSs from both mushrooms share high similarities in terms of physical properties, structural properties and domain distribution. Protein-protein docking analysis revealed that both GlCBS and LrCBS potentially modulate the C-terminal domain of ACE (C-ACE) activity via regulation of chloride activation and/or prevention of substrate entry. GICBS and LrCBS were also shown to interact with ACE at the same region that presumably inhibits the function of ACE.
The Omicron variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now spread throughout the world. We used computational tools to assess the spike infectivity, transmission, and pathogenicity of Omicron (BA.1) and sub-variants (BA.1.1, BA.2, and BA.3) in this study. BA.1 has 39 mutations, BA.1.1 has 40 mutations, BA.2 has 31 mutations, and BA.3 has 34 mutations, with 21 shared mutations between all. We observed 11 common mutations in Omicron's receptor-binding domain (RBD) and sub-variants. In pathogenicity analysis, the Y505H, N786K, T95I, N211I, N856K, and V213R mutations in omicron and sub-variants are predicted to be deleterious. Due to the major effect of the mutations characterizing in the RBD, we found that Omicron and sub-variants had a higher positive electrostatic surface potential. This could increase interaction between RBD and negative electrostatic surface potential human angiotensin-converting enzyme 2 (hACE2). Omicron and sub-variants had a higher affinity for hACE2 and the potential for increased transmission when compared to the wild-type (WT). Negative electrostatic potential of N-terminal domain (NTD) of the spike protein value indicates that the Omicron variant binds receptors less efficiently than the WT. Given that at least one receptor is highly expressed in lung and bronchial cells, the electrostatic potential of NTD negative value could be one of the factors contributing to why the Omicron variant is thought to be less harmful to the lower respiratory tract. Among Omicron sub-lineages, BA.2 and BA.3 have a higher transmission potential than BA.1 and BA.1.1. We predicted that mutated residues in BA.1.1 (K478), BA.2 (R400, R490, and R495), and BA.3 (R397 and H499) formation of new salt bridges and hydrogen bonds. Omicron and sub-variant mutations at Receptor-binding Motif (RBM) residues such as Q493R, N501Y, Q498, T478K, and Y505H all contribute significantly to binding affinity with human ACE2. Interactions with Omicron variant mutations at residues 493, 496, 498, and 501 seem to restore ACE2 binding effectiveness lost due to other mutations like K417N.
To determine whether quaternary ammonium (k21) binds to Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) spike protein via computational molecular docking simulations, the crystal structure of the SARS-CoV-2 spike receptor-binding domain complexed with ACE-2 (PDB ID: 6LZG) was downloaded from RCSB PD and prepared using Schrodinger 2019-4. The entry of SARS-CoV-2 inside humans is through lung tissues with a pH of 7.38-7.42. A two-dimensional structure of k-21 was drawn using the 2D-sketcher of Maestro 12.2 and trimmed of C18 alkyl chains from all four arms with the assumption that the core moiety k-21 was without C18. The immunogenic potential of k21/QA was conducted using the C-ImmSim server for a position-specific scoring matrix analyzing the human host immune system response. Therapeutic probability was shown using prediction models with negative and positive control drugs. Negative scores show that the binding of a quaternary ammonium compound with the spike protein's binding site is favorable. The drug molecule has a large Root Mean Square Deviation fluctuation due to the less complex geometry of the drug molecule, which is suggestive of a profound impact on the regular geometry of a viral protein. There is high concentration of Immunoglobulin M/Immunoglobulin G, which is concomitant of virus reduction. The proposed drug formulation based on quaternary ammonium to characterize affinity to the SARS-CoV-2 spike protein using simulation and computational immunological methods has shown promising findings.
Hypertension is one of the major causes of cardiovascular-related diseases, which is highly associated with angiotensin-I-converting enzyme (ACE) activity and oxidative stress. In this study, winged bean seed (WBS), a potential source of protein, was utilised for the production of bifunctional proteolysate and biopeptides with ACE inhibitory and antioxidative properties. An enzymatic approach was applied, coupled with pretreatment of shaking and centrifuging techniques to remove endogenous ACE inhibitors prior to proteolysis. ACE inhibition reached its highest activity, 78.5%, after 12 h proteolysis while antioxidative activities, determined using assays involving DPPH˙ radical scavenging activity and metal ion-chelating activity, reached peaks of 65.0% and 65.7% at 8 h and 14 h, respectively. The said bioactivities were proposed to share some common structural requirements among peptides. A two-dimensional approach was employed for characterisation of effective peptides based on hydrophobicity, using RP-HPLC, and isoelectric property, using isoelectric focusing technique. Results revealed that acidic and basic peptides with partially higher hydrophobicity provided higher ACE inhibition activity than did neutral peptides. Finally, by using Q-TOF mass spectrometry, two peptide sequences (YPNQKV and FDIRA) with ACE inhibitory and antioxidative activities were successfully matched with a database. This study indicates that the WBS proteolysate can be a potential bifunctional food ingredient as the identified biopeptides demonstrated both ACE inhibitory and antioxidative activities in vitro.
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.
Three novel peptide sequences identified from palm kernel cake (PKC) generated protein hydrolysate including YLLLK, WAFS and GVQEGAGHYALL were used for stability study against angiotensin-converting enzyme (ACE), ACE-inhibition kinetics and molecular docking studies. Results showed that the peptides were degraded at different cleavage degrees of 94%, 67% and 97% for YLLLK, WAFS and GVQEGAGHYALL, respectively, after 3 h of incubation with ACE. YLLLK was found to be the least stable (decreased ACE-inhibitory activity) compared to WAFS and GVQEGAGHYALL (increased ACE-inhibitory activity). YLLLK showed the lowest Ki (1.51 mM) in inhibition kinetics study when compared to WAFS and GVQEGAGHYALL with Ki of 2 mM and 3.18 mM, respectively. In addition, ACE revealed the lowest Kmapp and Vmaxapp and higher catalytic efficiency (CE) in the presence of YLLLK at different concentrations, implying that the enzyme catalysis decreased and hence the inhibition mode increased. Furthermore, YLLLK showed the lowest docking score of -8.224 and seven interactions with tACE, while peptide GVQEGAGHYALL showed the higher docking score of -7.006 and five interactions with tACE.
Chicken skin gelatin hydrolysates and peptides with angiotensin converting enzyme inhibitory (ACEI) activity were produced enzymatically using alcalase, pronase E, and collagenase before fractionation into
Coronavirus-like organisms have been previously identified in Arthropod ectoparasites (such as ticks and unfed cat flea). Yet, the question regarding the possible role of these arthropods as SARS-CoV-2 passive/biological transmission vectors is still poorly explored. In this study, we performed in silico structural and binding energy calculations to assess the risks associated with possible ectoparasite transmission. We found sufficient similarity between ectoparasite ACE and human ACE2 protein sequences to build good quality 3D-models of the SARS-CoV-2 Spike:ACE complex to assess the impacts of ectoparasite mutations on complex stability. For several species (e.g., water flea, deer tick, body louse), our analyses showed no significant destabilisation of the SARS-CoV-2 Spike:ACE complex, suggesting these species would bind the viral Spike protein. Our structural analyses also provide structural rationale for interactions between the viral Spike and the ectoparasite ACE proteins. Although we do not have experimental evidence of infection in these ectoparasites, the predicted stability of the complex suggests this is possible, raising concerns of a possible role in passive transmission of the virus to their human hosts.
Garlic protein (GP) was enzymatically hydrolyzed using pepsin and trypsin followed by the evaluation of antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities of GP and its hydrolysates. The antihypertensive effects of GP and its hydrolysates were determined in vivo. The results showed that GP and its hydrolysates namely GPH-P (pepsin) and GPH-T (trypsin) possessed appreciable antioxidant and ACE inhibitory activities. The ACE inhibitory activity of GP, GPH-T, and GPH-P was in consistent with their antioxidant activities. GP and its hydrolysates offered significant protective effects against H2 O2 -induced oxidative damage (p
This study aims to optimize enzymatic hydrolysis process for producing angiotensin I-converting enzyme (ACE) inhibitory peptides from protein hydrolysate of shortfin scad (Decapterus Macrosoma) waste (SWH). The enzymatic hydrolysis conditions, namely the temperature (40, 50, 60°C), time (B: 60, 120, 180 min), pH (C: 7, 8, 9) and enzyme substrate concentrations (D: 1, 2, 3%) on yield, degree of hydrolysis (DH) and ACE-inhibitory activity were analysed. Responses were optimized using the response surface methodology (RSM) by employing four factors, 3-levels and the Central Composite Design (CCD). The optimized conditions were further validated to indicate the validity of the prediction model. The optimal conditions obtained for the hydrolysis conditions were at temperature of 50°C, time of 60 min, pH of 9 and enzyme to substrate concentration of 2.92%. The experimental result for yield was lower than the predicted value, as generated by RSM. However, the degree of hydrolysis of SWH was higher than the predicted value. The ACE inhibitory activity of SWH was 79.34%, and showed lower than the predicted value. Therefore, the optimized conditions of SWH served as good conditions for the production of bioactive peptide with high ACE inhibitory activity.
Angiotensin I-converting enzyme (ACE) inhibitors derived from foods are valuable auxiliaries to agents such as captopril. Eight highly functional ACE inhibitory peptides from the mushroom, Agaricus bisporus, were identified by LC-MS/MS. Among these peptides, the most potent ACE inhibitory activity was exhibited by AHEPVK, RIGLF and PSSNK with IC₅₀ values of 63, 116 and 129 μM, respectively. These peptides exhibited high ACE inhibitory activity after gastrointestinal digestion. Lineweaver-Burk plots suggested that AHEPVK and RIGLF act as competitive inhibitors against ACE, whereas PSSNK acts as a non-competitive inhibitor. Mushrooms can be a good component of dietary supplement due to their readily available source and, in addition, they rarely cause food allergy. Compared to ACE inhibitory peptides isolated from other edible mushrooms, AHEPVK, RIGLF and PSSNK have lower IC₅₀ values. Therefore, these peptides may serve as an ideal ingredient in the production of antihypertensive supplements.
Systemic lupus erythematosus (SLE) is an autoimmune disease that causes systemic damage, involving auto-reactive antibodies and over-deposition of immune complexes. Susceptibility to SLE is believed to be multifactorial, and genetics is one of the proven etiological factors; it can affect SLE development, severity and prognosis. We investigated a possible association between the angiotensin-converting enzyme gene and susceptibility to SLE in the Malaysian population. PCR was employed for the determination of I/D dimorphism of this gene. The I allele was more frequent than the D allele in both the SLE patients (N = 170) and healthy controls (N = 190). However, there was no significant difference in the distribution of these two alleles between both groups studied (χ(2) = 0.284, P > 0.05). Interestingly, the DD homozygous genotype scored notably higher in the healthy control group (χ(2) = 7.568, P < 0.05), while the ID heterozygote was observed to be significantly associated with SLE (χ(2) = 11.143, P < 0.05). In conclusion, with respect to the Malaysian population, the DD genotype might play a protective role in the development of SLE while in contrast, those who carry the ID genotype might be at potential risk for onset of this disease.
This study aims to evaluate the in vitro angiotensin-converting enzyme (ACE) inhibition activity of different extracts of Orthosiphon stamineus (OS) leaves and their main flavonoids, namely rosmarinic acid (RA), sinensetin (SIN), eupatorin (EUP) and 3'-hydroxy-5,6,7,4'-tetramethoxyflavone (TMF). Furthermore, to identify possible mechanisms of action based on structure-activity relationships and molecular docking. The in vitro ACE inhibition activity relied on determining hippuric acid (HA) formation from ACE-specific substrate (hippuryl-histidyl-leucine (HHL)) by the action of ACE enzyme. A High Performance Liquid Chromatography method combined with UV detection was developed and validated for measurement the concentration of produced HA. The chelation ability of OS extract and its reference compounds was evaluated by tetramethylmurexide reagent. Furthermore, molecular docking study was performed by LeadIT-FlexX: BioSolveIT's LeadIT program. OS ethanolic extract (OS-E) exhibited highest inhibition and lowest IC50 value (45.77 ± 1.17 µg/mL) against ACE compared to the other extracts. Among the tested reference compounds, EUP with IC50 15.35 ± 4.49 µg/mL had highest inhibition against ACE and binding ability with Zn (II) (56.03% ± 1.26%) compared to RA, TMF and SIN. Molecular docking studies also confirmed that flavonoids inhibit ACE via interaction with the zinc ion and this interaction is stabilized by other interactions with amino acids in the active site. In this study, we have demonstrated that changes in flavonoids active core affect their capacity to inhibit ACE. Moreover, we showed that ACE inhibition activity of flavonoids compounds is directly related to their ability to bind with zinc ion in the active site of ACE enzyme. It was also revealed that OS extract contained high amount of flavonoids other than RA, TMF, SIN and EUP. As such, application of OS extract is useful as inhibitors of ACE.
Pleurotus pulmonarius (grey oyster mushroom) has been acknowledged as a recuperative agent for many diseases in addition to its recognition as a nutritious provision. We performed a study on P. pulmonarius mycelium for an antihypertensive effect via the angiotensin-converting enzyme inhibitory activity. The preliminary assay on the mycelial water extract demonstrated that the angiotensin-converting enzyme inhibitory activity had an IC50 value of 720 µg/mL. Further protein purifications via ammonium sulphate precipitation and RP-HPLC resulted in 60× stronger angiotensin-converting enzyme inhibitory activity than that of the mycelial water extract (IC50 = 12 µg/mL). Protein identification and characterisation by MALDI-TOF/TOF, later corroborated by LC-MS/MS, indicated three proteins that are responsible for the blood pressure lowering effects via different mechanisms: serine proteinase inhibitor-like protein, nitrite reductase-like protein, and DEAD/DEAH box RNA helicase-like protein.