Displaying publications 61 - 80 of 107 in total

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  1. Fulltext Immunodominant IgM and IgG Epitopes Recognized by Antibodies Induced in Enterovirus A71-Associated Hand, Foot and Mouth Disease Patients
    Aw-Yong KL, Sam IC, Koh MT, Chan YF
    PLoS One, 2016;11(11):e0165659.
    PMID: 27806091 DOI: 10.1371/journal.pone.0165659
    Enterovirus A71 (EV-A71) is one of the main causative agents of hand, foot and mouth disease (HFMD). Unlike other enteroviruses that cause HFMD, EV-A71 is more frequently associated with severe neurological complications and fatality. To date, no effective licensed antivirals are available to combat EV-A71 infection. Little is known about the immunogenicity of viral non-structural proteins in humans. Previous studies have mainly focused on characterization of epitopes of EV-A71 structural proteins by using immunized animal antisera. In this study, we have characterized human antibody responses against the structural and non-structural proteins of EV-A71. Each viral protein was cloned and expressed in either bacterial or mammalian systems, and tested with antisera by western blot. Results revealed that all structural proteins (VP1-4), and non-structural proteins 2A, 3C and 3D were targets of EV-A71 IgM, whereas EV-A71 IgG recognized all the structural and non-structural proteins. Sixty three synthetic peptides predicted to be immunogenic in silico were synthesized and used for the characterization of EV-A71 linear B-cell epitopes. In total, we identified 22 IgM and four IgG dominant epitopes. Synthetic peptide PEP27, corresponding to residues 142-156 of VP1, was identified as the EV-A71 IgM-specific immunodominant epitope. PEP23, mapped to VP1 41-55, was recognized as the EV-A71 IgG cross-reactive immunodominant epitope. The structural protein VP1 is the major immunodominant site targeted by anti-EV-A71 IgM and IgG antibodies, but epitopes against non-structural proteins were also detected. These data provide new understanding of the immune response to EV-A71 infection, which benefits the development of diagnostic tools, potential therapeutics and subunit vaccine candidates.
    Matched MeSH terms: Peptides/chemistry
  2. Fulltext Fibrillary deposits: amyloids and tactoids
    Looi LM
    Malays J Pathol, 1995 Jun;17(1):1-10.
    PMID: 8906998
    Two forms of abnormal fibrillary protein deposition are considered: amyloidosis and fibrillary (immunotactoid) glomerulonephritis. Amyloid is characterised by an antiparallel, beta-pleated configuration which imparts to it a unique apple-green birefringence after Congo red staining. Inspite of its fairly constant physical properties, the chemical composition of amyloid fibrils is amazingly diverse, encomposing AA protein, light chain fragments, transthyretin, procalcitonin, islet amyloid polypeptide, atrial natriuretic peptides, beta-amyloid protein, beta-2-microglobulin, cystatin C, gelsolin, apolipoprotein A1, lyzozyme and their mutant variants. Amyloid P component and heparan sulphate proteoglycan are ubiquitous non-fibrillary amyloid components which have significant roles in the amyloidogenetic process, as do also precursor fibril proteins. Different amyloid fibril proteins relate to different amyloidosis syndromes and different histological patterns, and provide the basis for new diagnostic approaches to this disorder. Glomerular deposits in fibrillary glomerulonephritis (FGN), although often mistaken for amyloid, differ from it in its negative Congophilia, wider fibril width and highly organised, microtubular-tactoidal appearance ultrastructurally. FGN is essentially a primary glomerulopathy resulting in progressive renal failure. Despite certain differences, intriguing similarities between both entities of fibrillary deposition pose a challenge to researchers as to the mechanisms of abnormal protein crystallization and fibril formation in tissues.
    Matched MeSH terms: Amyloid beta-Peptides/chemistry
  3. Fulltext Fluorine-19 Magnetic Resonance Imaging for Detection of Amyloid β Oligomers Using a Keto Form of Curcumin Derivative in a Mouse Model of Alzheimer's Disease
    Yanagisawa D, Ibrahim NF, Taguchi H, Morikawa S, Tomiyama T, Tooyama I
    Molecules, 2021 Mar 04;26(5).
    PMID: 33806326 DOI: 10.3390/molecules26051362
    Recent evidence suggests that the formation of soluble amyloid β (Aβ) aggregates with high toxicity, such as oligomers and protofibrils, is a key event that causes Alzheimer's disease (AD). However, understanding the pathophysiological role of such soluble Aβ aggregates in the brain in vivo could be difficult due to the lack of a clinically available method to detect, visualize, and quantify soluble Aβ aggregates in the brain. We had synthesized a novel fluorinated curcumin derivative with a fixed keto form, named as Shiga-Y51, which exhibited high selectivity to Aβ oligomers in vitro. In this study, we investigated the in vivo detection of Aβ oligomers by fluorine-19 (19F) magnetic resonance imaging (MRI) using Shiga-Y51 in an APP/PS1 double transgenic mouse model of AD. Significantly high levels of 19F signals were detected in the upper forebrain region of APP/PS1 mice compared with wild-type mice. Moreover, the highest levels of Aβ oligomers were detected in the upper forebrain region of APP/PS1 mice in enzyme-linked immunosorbent assay. These findings suggested that 19F-MRI using Shiga-Y51 detected Aβ oligomers in the in vivo brain. Therefore, 19F-MRI using Shiga-Y51 with a 7 T MR scanner could be a powerful tool for imaging Aβ oligomers in the brain.
    Matched MeSH terms: Amyloid beta-Peptides/chemistry
  4. Simulated gastrointestinal digestion of camel and bovine casein hydrolysates: Identification and characterization of novel anti-diabetic bioactive peptides
    Mudgil P, Kamal H, Priya Kilari B, Mohd Salim MAS, Gan CY, Maqsood S
    Food Chem, 2021 Aug 15;353:129374.
    PMID: 33740505 DOI: 10.1016/j.foodchem.2021.129374
    Camel milk proteins are an important substrate for bioactive peptides generation. This study investigates in-vitro antidiabetic effect (via inhibition of α-amylase (AA), α-glucosidase (AG) and dipeptidyl peptidase IV (DPP-IV)) of bovine (BC) and camel casein (CC) hydrolysates. Further, effect of simulated gastrointestinal digestion (SGID) on inhibitory potential of generated hydrolysates was also explored. Both BC and CC hydrolysates displayed potent inhibitory properties against AA (IC50 value- 0.58 & 0.59 mg/mL), AG (IC50 value- 1.04 & 0.59 mg/mL) and DPP-IV (IC50 value- 0.62 & 0.66 mg/mL), respectively. Among different peptides identified in BC and CC hydrolysates, it was observed that FLWPEYGAL was predicted to be most potent inhibitory peptide against AA. While LPTGWLM, MFE and GPAHCLL as most active inhibitor of AG and HLPGRG, QNVLPLH and PLMLP were predicted to be active against DPP-IV. Overall, BC and CC hydrolysates can be proposed to be used in different food formulations as functional antidiabetic agents.
    Matched MeSH terms: Peptides/chemistry
  5. Expression and characterization of anticoagulant activity of salivary protein alALP from Asian tiger mosquito Aedes albopictus
    Li XP, Lin D, Zhang Y, Chen SQ, Bai HQ, Zhang SN, et al.
    Trop Biomed, 2020 Mar 01;37(1):116-126.
    PMID: 33612723
    Several bioactive molecules isolated from the saliva of blood-sucking arthropods, such as mosquitoes, have been shown to exhibit potential anticoagulant function. We have previously identified a 30kDa allergen named Aegyptin-like protein (alALP), which is highly homologous to Aegyptin, from the salivary glands of female Aedes albopictus (Asian tiger mosquito). In this study, we identified the conserved functional domain of alALP by using bioinformatic tools, and expressed the His-tagged alALP recombinant protein in sf9 insect cells by generation and transfection of a baculoviral expression plasmid carrying the fulllength cDNA of alALP. We purified this recombinant protein and examined its function on the inhibition of blood coagulation. The results showed that the purified His-alALP prolonged the Activated Partial Thromboplastin Time (APTT), Prothrombin Time (PT) and Thrombin Time (TT) in vitro as well as the Bleeding Time (BT) in vivo, which suggest that alALP could be a novel anticoagulant.
    Matched MeSH terms: Salivary Proteins and Peptides/chemistry*
  6. Fulltext In vitro anti-diabetic activities and chemical analysis of polypeptide-k and oil isolated from seeds of Momordica charantia (bitter gourd)
    Ahmad Z, Zamhuri KF, Yaacob A, Siong CH, Selvarajah M, Ismail A, et al.
    Molecules, 2012 Aug 10;17(8):9631-40.
    PMID: 22885359 DOI: 10.3390/molecules17089631
    The amino acid and fatty acid composition of polypeptide k and oil isolated from the seeds of Momordica charantia was analysed. The analysis revealed polypeptide k contained 9 out of 11 essential amino acids, among a total of 18 types of amino acids. Glutamic acid, aspartic acid, arginine and glycine were the most abundant (17.08%, 9.71%, 9.50% and 8.90% of total amino acids, respectively). Fatty acid analysis showed unusually high amounts of C18-0 (stearic acid, 62.31% of total fatty acid). C18-1 (oleic acid) and C18-2 (linoleic acid) were the other major fatty acid detected (12.53% and 10.40%, respectively). The oil was devoid of the short fatty acids (C4-0 to C8-0). Polypeptide k and oil were also subjected to in vitro α-glucosidase and α-amylase inhibition assays. Both polypeptide k and seed oil showed potent inhibition of α-glucosidase enzyme (79.18% and 53.55% inhibition, respectively). α-Amylase was inhibited by 35.58% and 38.02%, respectively. Collectively, the in vitro assay strongly suggests that both polypeptide k and seed oil from Momordica charantia are potent potential hypoglycemic agents.
    Matched MeSH terms: Peptides/chemistry
  7. Purification and characterisation of antibacterial peptide-containing compound derived from palm kernel cake
    Tan YN, Ayob MK, Wan Yaacob WA
    Food Chem, 2013 Jan 1;136(1):279-84.
    PMID: 23017424 DOI: 10.1016/j.foodchem.2012.08.012
    Palm kernel cake (PKC), the most useful by-product resulted from palm kernel oil production. In this study, PKC-derived protein product was found suitable for use as an antimicrobial agent with potent antibacterial activity, particularly against Bacillus species, after enzymatic hydrolysis with alcalase. The hydrolysate was further purified by gel filtration chromatography. The purified fraction was found to have 14.63±0.70% (w/w) protein, a molecular mass of 2.4kDa and low hemolytic activity (<50% hemolysis of human erythrocytes at concentration of 1000μg/ml). The presence of lysine and the major component lauric acid derivative, as indicated by electrospray ionisation-mass spectrometry (ESI-MS) direct infusion and nuclear magnetic resonance (NMR) spectroscopy, may have contributed to the antibacterial effect of purified PKC fraction. This study suggests that the antibacterial PKC compound may be not a pure peptide but instead a peptide-containing compound high in lauric acid derivative.
    Matched MeSH terms: Peptides/chemistry*
  8. Drug trapping and delivery for Alzheimer's diagnosis
    Jalil MA, Kamoldilok S, Saktioto T, Ong CT, Yupapin PP
    Artif Cells Blood Substit Immobil Biotechnol, 2012 Oct;40(5):303-8.
    PMID: 22384850 DOI: 10.3109/10731199.2012.657203
    In this investigation, a new design based on a PANDA ring resonator as an optical trapping tool for tangle protein, molecular motor storage, and delivery is proposed. The optical vortices are generated and the trapping mechanism is controlled in the same way as the conventional optical tweezers. The trapping force is produced by a combination of the gradient field and scattering photons. The required molecular volume is trapped and moved dynamically within the molecular network. The tangle protein and molecular motor can be transported and delivered to the required destinations for Alzheimer's diagnosis by molecular buffer and bus network.
    Matched MeSH terms: Amyloid beta-Peptides/chemistry
  9. The production and characterisation of trichotoxin peptaibols, by Trichoderma asperellum
    Chutrakul C, Alcocer M, Bailey K, Peberdy JF
    Chem Biodivers, 2008 Sep;5(9):1694-706.
    PMID: 18816522 DOI: 10.1002/cbdv.200890158
    Trichoderma spp. are regularly found as a constituent of the mycoflora of many soils and are noted for their antagonistic activity against bacteria and other fungi. This latter property is the basis for the widespread interest in their use in the biological control of soil-borne fungal plant pathogens. This antagonism is partly based on their ability to produce an impressive inventory of secondary metabolites. An important group of bioactive metabolites produced by Trichoderma spp. are the non-ribosomal peptides (NRPs), especially the peptaibols. A virulent antagonistic strain, T. asperellum, which had been used in biological control strategies in Malaysia and previously examined for mycolytic enzyme production, has been studied for its potential for peptaibol production. The present research demonstrated the ability of T. asperellum to produce at least two metabolites which were identified as acid trichotoxin 1704E (Ac-Aib-Gly-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Ala-Ala-Aib-Pro-Leu-Aib-Iva-Glu-Vol) and neutral trichotoxin 1717A (Ac-Aib-Gly-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Ala-Aib-Aib-Pro-Leu-Aib-Iva-Gln-Vol). Addition of free Aib to the culture medium enhanced the production of trichotoxins. Biological activity of these substances was investigated against Bacillus stearothermophilus. The general characteristics of peptaibols, also found in the trichotoxins, include the presence of high proportions of the uncommon amino acid Aib, the protection of the N- and C-termini by an acetyl group and reduction of the C-terminus to 2-amino alcohols, respectively, amphipathy and microheterogeneity.
    Matched MeSH terms: Peptides/chemistry*
  10. Dengue envelope domain III-peptide binding analysis via tryptophan fluorescence quenching assay
    Baharuddin A, Amir Hassan A, Othman R, Xu Y, Huang M, Ario Tejo B, et al.
    Chem Pharm Bull (Tokyo), 2014;62(10):947-55.
    PMID: 25273053
    In the efforts to find an anti-viral treatment for dengue, a simple tryptophan fluorescence-screening assay aimed at identifying dengue domain III envelope (EIII) protein inhibitors was developed. Residue Trp391 of EIII was used as an intrinsic probe to monitor the change in fluorescence of the tryptophan residue upon binding to a peptide. The analysis was based on the electron excitation at 280 nm and fluorescence emission at 300-400 nm of EIII, followed by quenching of fluorescence in the presence of potential peptidic inhibitors coded DS36wt, DS36opt, DN58wt and DN58opt. The present study found that the fluorescence of the recombinant EIII was quenched following the binding of DS36opt, DN58wt and DN58opt in a concentration-dependent manner. Since the λmax for emission remained unchanged, the effect was not due to a change in the environment of the tryptophan side chain. In contrast, a minimal fluorescence-quenching effect of DS36wt at 20 and 40 µM suggested that the DS36wt does not have any binding ability to EIII. This was supported by a simple native-page gel retardation assay that showed a band shift of EIII domain when incubated with DS36opt, DN58wt and DN58opt but not with DS36wt. We thus developed a low-cost and convenient spectrophotometric binding assay for the analysis of EIII-peptide interactions in a drug screening application.
    Matched MeSH terms: Peptides/chemistry*
  11. Recent advances in food biopeptides: production, biological functionalities and therapeutic applications
    Saadi S, Saari N, Anwar F, Abdul Hamid A, Ghazali HM
    Biotechnol Adv, 2014 12 12;33(1):80-116.
    PMID: 25499177 DOI: 10.1016/j.biotechadv.2014.12.003
    The growing momentum of several common life-style diseases such as myocardial infarction, cardiovascular disorders, stroke, hypertension, diabetes, and atherosclerosis has become a serious global concern. Recent developments in the field of proteomics offering promising solutions to solving such health problems stimulates the uses of biopeptides as one of the therapeutic agents to alleviate disease-related risk factors. Functional peptides are typically produced from protein via enzymatic hydrolysis under in vitro or in vivo conditions using different kinds of proteolytic enzymes. An array of biological activities, including antioxidative, antihypertensive, antidiabetic and immunomodulating has been ascribed to different types of biopeptides derived from various food sources. In fact, biopeptides are nutritionally and functionally important for regulating some physiological functions in the body; however, these are yet to be extensively addressed with regard to their production through advance strategies, mechanisms of action and multiple biological functionalities. This review mainly focuses on recent biotechnological advances that are being made in the field of production in addition to covering the mode of action and biological activities, medicinal health functions and therapeutic applications of biopeptides. State-of-the-art strategies that can ameliorate the efficacy, bioavailability, and functionality of biopeptides along with their future prospects are likewise discussed.
    Matched MeSH terms: Peptides/chemistry*
  12. Hepatitis B virus peptide inhibitors: solution structures and interactions with the viral capsid
    Muhamad A, Ho KL, Rahman MB, Tejo BA, Uhrín D, Tan WS
    Org Biomol Chem, 2015 Jul 28;13(28):7780-9.
    PMID: 26100394 DOI: 10.1039/c5ob00449g
    Hepatitis B virus (HBV) infection remains a health problem globally despite the availability of effective vaccines. In the assembly of the infectious virion, both the preS and S regions of the HBV large surface antigen (L-HBsAg) interact synergistically with the viral core antigen (HBcAg). Peptides preS and S based on the L-HBsAg were demonstrated as potential inhibitors to block the viral assembly. Therefore, the objectives of this study were to determine the solution structures of these peptides and study their interactions with HBcAg. The solution structures of these peptides were solved using (1)H, (13)C, and (15)N NMR spectroscopy. Peptide preS has several structured regions of β-turns at Ser7-Pro8-Pro9, Arg11-Thr12-Thr13 and Ser22-Thr23-Thr24 sequences whereas peptide S has only one structured region observed at Ser3-Asn4-His5. Both peptides contain bend-like structures surrounding the turn structures. Docking studies revealed that both peptides interacted with the immunodominant region of HBcAg located at the tip of the viral capsid spikes. Saturation Transfer Difference (STD) NMR experiments identified several aromatic residues in peptides preS and S that interact with HBcAg. This study provides insights into the contact regions of L-HBsAg and HBcAg at atomic resolution which can be used to design antiviral agents that inhibit HBV morphogenesis.
    Matched MeSH terms: Peptides/chemistry*
  13. An overview of antifungal peptides derived from insect
    Faruck MO, Yusof F, Chowdhury S
    Peptides, 2016 06;80:80-88.
    PMID: 26093218 DOI: 10.1016/j.peptides.2015.06.001
    Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases.
    Matched MeSH terms: Peptides/chemistry
  14. A novel single-domain peptide, anti-LPS factor from prawn: synthesis of peptide, antimicrobial properties and complete molecular characterization
    Arockiaraj J, Kumaresan V, Bhatt P, Palanisamy R, Gnanam AJ, Pasupuleti M, et al.
    Peptides, 2014 Mar;53:79-88.
    PMID: 24269604 DOI: 10.1016/j.peptides.2013.11.008
    In this study, we reported a complete molecular characterization including bioinformatics features, gene expression, peptide synthesis and its antimicrobial activities of an anti-lipopolysaccharide (LPS) factor (ALF) cDNA identified from the established cDNA library of freshwater prawn Macrobrachium rosenbergii (named as MrALF). The mature protein has an estimated molecular weight of 11.240 kDa with an isoelectric point of 9.46. The bioinformatics analysis showed that the MrALF contains an antimicrobial peptide (AMP) region between T54 and P77 with two conserved cysteine residues (Cys55 and Cys76) which have an anti-parallel β-sheet confirmation. The β-sheet is predicted as cationic with hydrophobic nature containing a net charge of +5. The depicted AMP region is determined to be amphipathic with a predicted hydrophobic face 'FPVFI'. A highest MrALF gene expression was observed in hemocytes and is up-regulated with virus [white spot syndrome baculovirus (WSBV)], bacteria (Aeromonas hydrophila) and Escherichia coli LPS at various time points. The LPS binding region of MrALF peptide was synthesized to study the antimicrobial property, bactericidal efficiency and hemolytic capacity. The peptide showed antimicrobial activity against both the Gram-negative and Gram-positive bacteria. The bactericidal assay showed that the peptide recognized the LPS of bacterial cell walls and binding on its substrate and thereby efficiently distinguishing the pathogens. The hemolytic activity of MrALF peptide is functioning in a concentration dependant manner. In summary, the comprehensive analysis of MrALF showed it to be an effective antimicrobial peptide and thus it plays a crucial role in the defense mechanism of M. rosenbergii.
    Matched MeSH terms: Peptides/chemistry*
  15. Fulltext Novel angiotensin I-converting enzyme inhibitory peptides derived from an edible mushroom, Pleurotus cystidiosus O.K. Miller identified by LC-MS/MS
    Lau CC, Abdullah N, Shuib AS
    BMC Complement Altern Med, 2013 Nov 11;13:313.
    PMID: 24215325 DOI: 10.1186/1472-6882-13-313
    BACKGROUND: Angiotensin I-converting enzyme (ACE) inhibitors have been reported to reduce mortality in patients with hypertension. Compared to chemosynthetic drugs, ACE inhibitors derived from natural sources such as food proteins are believed to be safer for consumption and to have fewer adverse effects. Some edible mushrooms have been reported to significantly reduce blood pressure after oral administration. In addition, mushrooms are known to be rich in protein content. This makes them a potential source of ACE inhibitory peptides. Hence, the objective of the current study was to isolate and characterise ACE inhibitory peptides from an edible mushroom, Pleurotus cystidiosus.

    METHODS: ACE inhibitory proteins were isolated from P. cystidiosus based on the bioassay guided purification steps, i.e. ammonium sulphate precipitation, reverse phase high performance liquid chromatography and size exclusion chromatography. Active fraction was then analysed by LC-MS/MS and potential ACE inhibitory peptides identified were chemically synthesized. Effect of in vitro gastrointestinal digestions on the ACE inhibitory activity of the peptides and their inhibition patterns were evaluated.

    RESULTS: Two potential ACE inhibitory peptides, AHEPVK and GPSMR were identified from P. cystidiosus with molecular masses of 679.53 and 546.36 Da, respectively. Both peptides exhibited potentially high ACE inhibitory activity with IC50 values of 62.8 and 277.5 μM, respectively. SEC chromatograms and BIOPEP analysis of these peptides revealed that the peptide sequence of the hexapeptide, AHEPVK, was stable throughout gastrointestinal digestion. The pentapeptide, GPSMR, was hydrolysed after digestion and it was predicted to release a dipeptide ACE inhibitor, GP, from its precursor. The Lineweaver-Burk plot of AHEPVK showed that this potent and stable ACE inhibitor has a competitive inhibitory effect against ACE.

    CONCLUSION: The present study indicated that the peptides from P. cystidiosus could be potential ACE inhibitors. Although these peptides had lower ACE inhibitory activity compared to commercial antihypertensive drugs, they are derived from mushroom which could be easily obtained and should have no side effects. Further in vivo studies can be carried out to reveal the clear mechanism of ACE inhibition by these peptides.

    Matched MeSH terms: Peptides/chemistry*
  16. Extraction of antioxidative and antihypertensive bioactive peptides from Parkia speciosa seeds
    Siow HL, Gan CY
    Food Chem, 2013 Dec 15;141(4):3435-42.
    PMID: 23993504 DOI: 10.1016/j.foodchem.2013.06.030
    Antioxidative and antihypertensive bioactive peptides were successfully derived from Parkia speciosa seed using alcalase. The effects of temperature (25 and 50 °C), substrate-to-enzyme ratio (S/E ratio, 20 and 50), and incubation time (0.5, 1, 2 and 5h) were evaluated based on 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and angiotensin-converting enzyme (ACE) assays. Bioactive peptide extracted at a hydrolysis condition of: temperature=50 °C, S/E ratio=50 and incubation time=2h, exhibited the highest DPPH radical scavenging activity (2.9 mg GAE/g), reducing power (11.7 mM) and %ACE-inhibitory activity (80.2%). The sample was subsequently subjected to fractionation and the peptide fraction of <10 kDa showed the strongest bioactivities. A total of 29 peptide sequences from peptide fraction of <10 kDa were identified as the most potent contributors to the bioactivities. These novel bioactive peptides were suggested to be beneficial to nutraceutical and food industries.
    Matched MeSH terms: Peptides/chemistry*
  17. Fulltext Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora) Hydrolysates
    Ghanbari R, Zarei M, Ebrahimpour A, Abdul-Hamid A, Ismail A, Saari N
    Int J Mol Sci, 2015 Dec 04;16(12):28870-85.
    PMID: 26690117 DOI: 10.3390/ijms161226140
    In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora) hydrolysates, which had been prepared by alcalase, papain, bromelain, flavourzyme, pepsin, and trypsin under their optimum conditions. The alcalase hydrolysate showed the highest ACE inhibitory activity (69.8%) after 8 h of hydrolysis while the highest anti-oxidative activities measured by 2,2-diphenyl 1-1-picrylhydrazyl radical scavenging (DPPH) (56.00%) and ferrous ion-chelating (FIC) (59.00%) methods were exhibited after 24 h and 8 h of hydrolysis, respectively. The ACE-inhibitory and anti-oxidative activities displayed dose-dependent trends, and increased with increasing protein hydrolysate concentrations. Moreover, strong positive correlations between angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities were also observed. This study indicates that A. lecanora hydrolysate can be exploited as a source of functional food owing to its anti-oxidant as well as anti-hypertension functions.
    Matched MeSH terms: Peptides/chemistry
  18. Anti-dengue virus serotype 2 activity and mode of action of a novel peptide
    Chew MF, Tham HW, Rajik M, Sharifah SH
    J Appl Microbiol, 2015 Oct;119(4):1170-80.
    PMID: 26248692 DOI: 10.1111/jam.12921
    To identify a novel antiviral peptide against dengue virus serotype 2 (DENV-2) by screening a phage display peptide library and to evaluate its in vitro antiviral activity and mode of action.
    Matched MeSH terms: Peptides/chemistry
  19. Bactericidal and fungistatic activity of peptide derived from GH18 domain of prawn chitinase 3 and its immunological functions during biological stress
    Ravichandran G, Kumaresan V, Mahesh A, Dhayalan A, Arshad A, Arasu MV, et al.
    Int J Biol Macromol, 2018 Jan;106:1014-1022.
    PMID: 28837852 DOI: 10.1016/j.ijbiomac.2017.08.098
    Chitinases play a vital role during the pathogenic invasion and immunosuppression in various organisms including invertebrates and vertebrates. In this study, we have investigated the participation of MrChit-3 (Macrobrachium rosenbergii Chitinase-3) during host-pathogenic interaction in freshwater prawn, M. rosenbergii. Quantitative real-time PCR analysis showed that the expression of MrChit-3 was up-regulated during bacterial, viral and laminarin challenge. Moreover, to understand the antimicrobial role of the GH18 domain, a putative membrane-targeting antimicrobial peptide (MrVG) was identified from the GH18 domain region of the protein and it was chemically synthesized. Physico-chemical features of the GH18 derived antimicrobial peptide (AMP) was assessed by various in silico tools and the antimicrobial property of the peptide was confirmed from in vitro studies. The membrane targeting mechanism of the peptide was determined by flow cytometry (FACS) and scanning electron microscope (SEM) analysis. Interestingly, the peptide was able to inhibit the growth of a chitinolytic fungal pathogen, Aspergillus niger, which was isolated from the shells of M. rosenbergii. The toxicity studies such as hemolysis activity on human blood erythrocytes and cell viability assay with primary kidney cells, HEK293 of MrVG revealed that the peptide was not involved in inducing any toxicity.
    Matched MeSH terms: Antimicrobial Cationic Peptides/chemistry
  20. Fulltext Targeted Delivery of Cell Penetrating Peptide Virus-like Nanoparticles to Skin Cancer Cells
    Gan BK, Yong CY, Ho KL, Omar AR, Alitheen NB, Tan WS
    Sci Rep, 2018 05 31;8(1):8499.
    PMID: 29855618 DOI: 10.1038/s41598-018-26749-y
    Skin cancer or cutaneous carcinoma, is a pre-eminent global public health problem with no signs of plateauing in its incidence. As the most common treatments for skin cancer, surgical resection inevitably damages a patient's appearance, and chemotherapy has many side effects. Thus, the main aim of this study was to screen for a cell penetrating peptide (CPP) for the development of a targeting vector for skin cancer. In this study, we identified a CPP with the sequence NRPDSAQFWLHH from a phage displayed peptide library. This CPP targeted the human squamous carcinoma A431 cells through an interaction with the epidermal growth factor receptor (EGFr). Methyl-β-cyclodextrin (MβCD) and chlorpromazine hydrochloride (CPZ) inhibited the internalisation of the CPP into the A431 cells, suggesting the peptide entered the cells via clathrin-dependent endocytosis. The CPP displayed on hepatitis B virus-like nanoparticles (VLNPs) via the nanoglue successfully delivered the nanoparticles into A431 cells. The present study demonstrated that the novel CPP can serve as a ligand to target and deliver VLNPs into skin cancer cells.
    Matched MeSH terms: Cell-Penetrating Peptides/chemistry
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