Displaying publications 1 - 20 of 27 in total

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  1. Structure-informed separation of bioactive peptides
    Acquah C, Chan YW, Pan S, Agyei D, Udenigwe CC
    J Food Biochem, 2019 01;43(1):e12765.
    PMID: 31353493 DOI: 10.1111/jfbc.12765
    The application of proteomic and peptidomic technologies for food-derived bioactive peptides is an emerging field in food sciences. These technologies include the use of separation tools coupled to a high-resolution spectrometric and bioinformatic tools for prediction, identification, sequencing, and characterization of peptides. To a large extent, one-dimensional separation technologies have been extensively used as a continuous tool under different optimized conditions for the identification and analysis of food peptides. However, most one-dimensional separation technologies are fraught with significant bottlenecks such as insufficient sensitivity and specificity limits for complex samples. To address this limitation, separation systems based on orthogonal, multidimensional principles, which allow for the coupling of more than one analytical separation tool with different operational principles, provide a higher separation power than one-dimensional separation tools. This review describes the structure-informed separation and purification of protein hydrolyzates to obtain peptides with desirable bioactivities. PRACTICAL APPLICATIONS: Application of bioactive peptides in the formulation of functional foods, nutraceuticals, and therapeutic agents have increasingly gained scholarly and industrial attention. The bioactive peptides exist originally in protein sources and are only active after hydrolysis of the parent protein. Currently, several tools can be configured in one-dimensional or multidimensional systems for the separation and purification of protein hydrolyzates. The separations are informed by the structural properties such as the molecular weight, charge, hydrophobicity or hydrophilicity, and the solubility of peptides. This review provides a concise discussion on the commonly used analytical tools, their configurations, advantages and challenges in peptide separation. Emphasis is placed on how the structural properties of peptides assist in the separation and purification processes and the concomitant effect of the separation on peptide bioactivity.
    Matched MeSH terms: Peptides/isolation & purification*
  2. Hemoglobin Tak in a newborn Malay
    Lie-Injo LE, Randhawa ZI, Ganesan J, Kane J, Peterson D
    Hemoglobin, 1977;1(8):747-57.
    PMID: 604313
    The trait condition for hemoglobin Tak, was found in a 4-day old newborn Malay who suffered from severe neonatal jaundice. The beta chain of the abnormal hemoglobin was elongated by 11 residues at the C-terminus and had the same structure as reported for Hb Tak. The mother was heterozygous for this abnormal hemoglobin, the father was normal. The mother and child, 4 years later, did not show clinical or hematological symptoms except definitely increased resistance of their erythrocytes to hypotonic saline solutions and slight anisopoikilocytosis. The abnormal gene in the two reported Thai families and in our Malay family may have the same origin.
    Matched MeSH terms: Peptides/isolation & purification
  3. Antimicrobial peptides from different plant sources: Isolation, characterisation, and purification
    Tang SS, Prodhan ZH, Biswas SK, Le CF, Sekaran SD
    Phytochemistry, 2018 Oct;154:94-105.
    PMID: 30031244 DOI: 10.1016/j.phytochem.2018.07.002
    Antimicrobial peptides (AMPs), the self-defence products of organisms, are extensively distributed in plants. They can be classified into several groups, including thionins, defensins, snakins, lipid transfer proteins, glycine-rich proteins, cyclotides and hevein-type proteins. AMPs can be extracted and isolated from different plants and plant organs such as stems, roots, seeds, flowers and leaves. They perform various physiological defensive mechanisms to eliminate viruses, bacteria, fungi and parasites, and so could be used as therapeutic and preservative agents. Research on AMPs has sought to obtain more detailed and reliable information regarding the selection of suitable plant sources and the use of appropriate isolation and purification techniques, as well as examining the mode of action of these peptides. Well-established AMP purification techniques currently used include salt precipitation methods, absorption-desorption, a combination of ion-exchange and reversed-phase C18 solid phase extraction, reversed-phase high-performance liquid chromatography (RP-HPLC), and the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method. Beyond these traditional methods, this review aims to highlight new and different approaches to the selection, characterisation, isolation, purification, mode of action and bioactivity assessment of a range of AMPs collected from plant sources. The information gathered will be helpful in the search for novel AMPs distributed in the plant kingdom, as well as providing future directions for the further investigation of AMPs for possible use on humans.
    Matched MeSH terms: Antimicrobial Cationic Peptides/isolation & purification*
  4. Use of superparamagnetic beads for the isolation of a peptide with specificity to cymbidium mosaic virus
    Ooi DJ, Dzulkurnain A, Othman RY, Lim SH, Harikrishna JA
    J Virol Methods, 2006 Sep;136(1-2):160-5.
    PMID: 16781785
    A modified method for the rapid isolation of specific ligands to whole virus particles is described. Biopanning against cymbidium mosaic virus was carried out with a commercial 12-mer random peptide display library. A solution phase panning method was devised using streptavidin-coated superparamagnetic beads. The solution based panning method was more efficient than conventional immobilized target panning when using whole viral particles of cymbidium mosaic virus as a target. Enzyme-linked immunosorbent assay of cymbidium mosaic virus-binding peptides isolated from the library identified seven peptides with affinity for cymbidium mosaic virus and one peptide which was specific to cymbidium mosaic virus and had no significant binding to odontoglossum ringspot virus. This method should have broad application for the screening of whole viral particles towards the rapid development of diagnostic reagents without the requirement for cloning and expression of single antigens.
    Matched MeSH terms: Peptides/isolation & purification*
  5. Novel angiotensin I-converting enzyme inhibitory peptides derived from edible mushroom Agaricus bisporus (J.E. Lange) Imbach identified by LC-MS/MS
    Lau CC, Abdullah N, Shuib AS, Aminudin N
    Food Chem, 2014 Apr 1;148:396-401.
    PMID: 24262574 DOI: 10.1016/j.foodchem.2013.10.053
    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.
    Matched MeSH terms: Peptides/isolation & purification
  6. A review of fish-derived antioxidant and antimicrobial peptides: their production, assessment, and applications
    Najafian L, Babji AS
    Peptides, 2012 Jan;33(1):178-85.
    PMID: 22138166 DOI: 10.1016/j.peptides.2011.11.013
    Fishes are rich sources of structurally diverse bioactive compounds. In recent years, much attention has been paid to the existence of peptides with biological activities and proteins derived from foods that might have beneficial effects for humans. Antioxidant and antimicrobial peptides isolated from fish sources may be used as functional ingredients in food formulations to promote consumer health and improve the shelf life of food products. This paper presents an overview of the antioxidant and antimicrobial peptides derived from various fishes. In addition, we discuss the extraction of fish proteins, enzymatic production, and the techniques used to isolate and characterize these compounds. Furthermore, we review the methods used to assay the bioactivities and their applications in food and nutraceuticals.
    Matched MeSH terms: Peptides/isolation & purification
  7. Enzyme-assisted extraction and identification of antioxidative and α-amylase inhibitory peptides from Pinto beans (Phaseolus vulgaris cv. Pinto)
    Ngoh YY, Gan CY
    Food Chem, 2016 Jan 1;190:331-7.
    PMID: 26212978 DOI: 10.1016/j.foodchem.2015.05.120
    Antioxidant and α-amylase inhibitor peptides were successfully extracted from Pinto bean protein isolate (PBPI) using Protamex. A factorial design experiment was conducted and the effects of extraction time, pH and temperature were studied. pH 7.5, extraction time of 1h, S/E ratio of 10 (w/w) and temperature of 50 °C gave the highest antioxidant activities (i.e., ABTS scavenging activity (53.3%) and FRAP value (3.71 mM)), whereas pH 6.5 with the same extraction time, S/E ratio and temperature, gave the highest α-amylase inhibitory activity (57.5%). It was then fractioned using membrane ultrafiltration with molecular weight cutoffs of 100, 50, 30, 10 and 3 kDa. Peptide fraction <3 kDa, which exhibited the highest antioxidant activities (i.e., ABTS (42.2%) and FRAP (0.81 mM)) and α-amylase inhibitory activity (62.1%), was then subjected to LCMS and MS/MS analyses. Six sequences were identified for antioxidant peptides, whereas seven peptides for α-amylase inhibitor.
    Matched MeSH terms: Peptides/isolation & purification*
  8. Fulltext Dielectrophoresis of Amyloid-Beta Proteins as a Microfluidic Template for Alzheimer's Research
    Al-Ahdal SA, Ahmad Kayani AB, Md Ali MA, Chan JY, Ali T, Adnan N, et al.
    Int J Mol Sci, 2019 Jul 23;20(14).
    PMID: 31340481 DOI: 10.3390/ijms20143595
    We employed dielectrophoresis to a yeast cell suspension containing amyloid-beta proteins (Aβ) in a microfluidic environment. The Aβ was separated from the cells and characterized using the gradual dissolution of Aβ as a function of the applied dielectrophoretic parameters. We established the gradual dissolution of Aβ under specific dielectrophoretic parameters. Further, Aβ in the fibril form at the tip of the electrode dissolved at high frequency. This was perhaps due to the conductivity of the suspending medium changing according to the frequency, which resulted in a higher temperature at the tips of the electrodes, and consequently in the breakdown of the hydrogen bonds. However, those shaped as spheroidal monomers experienced a delay in the Aβ fibril transformation process. Yeast cells exposed to relatively low temperatures at the base of the electrode did not experience a positive or negative change in viability. The DEP microfluidic platform incorporating the integrated microtip electrode array was able to selectively manipulate the yeast cells and dissolve the Aβ to a controlled extent. We demonstrate suitable dielectrophoretic parameters to induce such manipulation, which is highly relevant for Aβ-related colloidal microfluidic research and could be applied to Alzheimer's research in the future.
    Matched MeSH terms: Amyloid beta-Peptides/isolation & purification*
  9. Identification and molecular docking study of novel cholesterol esterase inhibitory peptides from camel milk proteins
    Mudgil P, Baby B, Ngoh YY, Vijayan R, Gan CY, Maqsood S
    J Dairy Sci, 2019 Dec;102(12):10748-10759.
    PMID: 31548068 DOI: 10.3168/jds.2019-16520
    Novel bioactive peptides from camel milk protein hydrolysates (CMPH) were identified and tested for inhibition of cholesterol esterase (CEase), and their possible binding mechanisms were elucidated by molecular docking. Papain-generated CMPH showed the highest degree of hydrolysis. All CMPH produced upon enzymatic degradation demonstrated a dramatic enhancement of CEase inhibition compared with intact camel milk proteins, with papain-generated hydrolysate P9 displaying the highest inhibition. Peptide identification and their modeling through PepSite 2 revealed that among 20 potential bioactive peptides in alcalase-generated hydrolysate A9, only 3 peptides, with sequences KFQWGY, SQDWSFY, and YWYPPQ, showed the highest binding toward CEase catalytic sites. Among 43 peptides in 9-h papain-generated hydrolysate P9, 4 peptides were found to be potent CEase inhibitors. Molecular docking revealed that WPMLQPKVM, CLSPLQMR, MYQQWKFL, and CLSPLQFR from P9 hydrolysates were able to bind to the active site of CEase with good docking scores and molecular mechanics-generalized born surface area binding energies. Overall, this is the first study reporting CEase inhibitory potential of peptides generated from milk proteins.
    Matched MeSH terms: Peptides/isolation & purification
  10. Discovery and Development of Novel Anti-fungal Peptides Against Foodspoiling Fungi
    Muhialdin BJ, Algboory HL, Mohammed NK, Kadum H, Hussin ASM, Saari N, et al.
    Curr Drug Discov Technol, 2020;17(4):553-561.
    PMID: 31309892 DOI: 10.2174/1570163816666190715120038
    BACKGROUND: Despite the extensive research carried out to develop natural antifungal preservatives for food applications, there are very limited antifungal agents available to inhibit the growth of spoilage fungi in processed foods. Scope and Approach: Therefore, this review summarizes the discovery and development of antifungal peptides using lactic acid bacteria fermentation to prevent food spoilage by fungi. The focus of this review will be on the identification of antifungal peptides, potential sources, the possible modes of action and properties of peptides considered to inhibit the growth of spoilage fungi. Key Findings and Conclusions: Antifungal peptides generated by certain lactic acid bacteria strains have a high potential for applications in a broad range of foods. The mechanism of peptides antifungal activity is related to their properties such as low molecular weight, concentration and secondary structure. The antifungal peptides were proposed to be used as bio-preservatives to reduce and/or replace chemical preservatives.
    Matched MeSH terms: Peptides/isolation & purification
  11. Detection of virulent Newcastle disease virus using a phage-capturing dot blot assay
    Lee TC, Yusoff K, Nathan S, Tan WS
    J Virol Methods, 2006 Sep;136(1-2):224-9.
    PMID: 16797732
    Newcastle disease virus (NDV) strains can be classified as virulent or avirulent based upon the severity of the disease. Differentiation of the virus into virulent and avirulent is necessary for effective control of the disease. Biopanning experiments were performed using a disulfide constrained phage displayed heptapeptide library against three pathotypes of NDV strains: velogenic (highly virulent), mesogenic (moderately virulent) and lentogenic (avirulent). A phage clone bearing the peptide sequence SWGEYDM capable of distinguishing virulent from avirulent NDV strains was isolated. This phage clone was employed as a diagnostic reagent in a dot blot assay and it successfully detected only virulent NDV strains.
    Matched MeSH terms: Peptides/isolation & purification
  12. 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/isolation & purification
  13. 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/isolation & purification
  14. 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/isolation & purification
  15. 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/isolation & purification
  16. 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/isolation & purification*
  17. Lymph node metastasis of primary endometrial cancers: Associated proteins revealed by MALDI imaging
    Mittal P, Klingler-Hoffmann M, Arentz G, Winderbaum L, Lokman NA, Zhang C, et al.
    Proteomics, 2016 06;16(11-12):1793-801.
    PMID: 27061135 DOI: 10.1002/pmic.201500455
    Metastasis is a crucial step of malignant progression and is the primary cause of death from endometrial cancer. However, clinicians presently face the challenge that conventional surgical-pathological variables, such as tumour size, depth of myometrial invasion, histological grade, lymphovascular space invasion or radiological imaging are unable to predict with accuracy if the primary tumour has metastasized. In the current retrospective study, we have used primary tumour samples of endometrial cancer patients diagnosed with (n = 16) and without (n = 27) lymph node metastasis to identify potential discriminators. Using peptide matrix assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI), we have identified m/z values which can classify 88% of all tumours correctly. The top discriminative m/z values were identified using a combination of in situ sequencing and LC-MS/MS from digested tumour samples. Two of the proteins identified, plectin and α-Actin-2, were used for validation studies using LC-MS/MS data independent analysis (DIA) and immunohistochemistry. In summary, MALDI-MSI has the potential to identify discriminators of metastasis using primary tumour samples.
    Matched MeSH terms: Peptides/isolation & purification*
  18. 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/isolation & purification
  19. Allelic variants of acidic proline-rich proteins observed in Japanese, Chinese, and Malays
    Shintani M, Minaguchi K, Suzuki K, Lim KA
    Biochem Genet, 1990 Apr;28(3-4):173-84.
    PMID: 2383244
    Three new variants of acidic proline-rich proteins (At, Au, Aw) were found in human parotid saliva by isoelectric focusing and basic gel electrophoresis. Electrophoretic comparison of the purified proteins and their tryptic peptides suggested minor charge and size differences from other acidic PRPs. Genetic and biochemical studies indicate that the At and Aw proteins are allelic products of the PRH1 locus. Gene frequencies of the At productive allele (PRH1(6)) in Japanese, Chinese, and Malays were 0.008, 0.012, and 0.004, respectively. The Au protein was also found in Japanese (2 in 746 samples), Chinese (1 in 215 samples), and Malays (1 in 220 samples), however, the Aw protein was found only in one Japanese (n = 746). These three proteins were not found in 106 Indian subjects.
    Matched MeSH terms: Peptides/isolation & purification
  20. Extraction and identification of α-amylase inhibitor peptides from Nephelium lappacheum and Nephelium mutabile seed protein using gastro-digestive enzymes
    Evaristus NA, Wan Abdullah WN, Gan CY
    Peptides, 2018 04;102:61-67.
    PMID: 29510154 DOI: 10.1016/j.peptides.2018.03.001
    The potential of N. lappacheum and N. mutabile seed as a source of α-amylase inhibitor peptides was explored based on the local traditional practice of using the seed. Different gastro-digestive enzymes (i.e. pepsin or chymotrypsin) or a sequential digestion were used to extract the peptides. The effects of digestion time and enzyme to substrate (E:S) ratio on the α-amylase inhibitory activity were investigated. Results showed that chymotrypsin was effective in producing the inhibitor peptides from rambutan seed protein at E:S ratio 1:20 for 1 h, whereas pepsin was more effective for pulasan seed protein under the same condition. A total of 20 and 31 novel inhibitor peptides were identified, respectively. These peptides could bind with the subsites of α-amylase (i.e. Trp58, Trp59, Tyr62, Asp96, Arg195, Asp197, Glu233, His299, Asp300, and His305) and formed a sliding barrier that preventing the formation of enzyme/substrate intermediate leading to lower α-amylase activity.
    Matched MeSH terms: Peptides/isolation & purification
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