Displaying publications 41 - 60 of 65 in total

Abstract:
Sort:
  1. Fulltext Expression, purification and characterization of the dimeric protruding domain of Macrobrachium rosenbergii nodavirus capsid protein expressed in Escherichia coli
    Chong LC, Ganesan H, Yong CY, Tan WS, Ho KL
    PLoS One, 2019;14(2):e0211740.
    PMID: 30707739 DOI: 10.1371/journal.pone.0211740
    Macrobrachium rosenbergii nodavirus (MrNV) is the causative agent of white tail disease (WTD) which seriously impedes the production of the giant freshwater prawn and has a major economic impact. MrNV contains two segmented RNA molecules, which encode the RNA dependent RNA polymerase (RdRp) and the capsid protein (MrNV-CP) containing 371 amino acid residues. MrNV-CP comprises of the Shell (S) and the Protruding (P) domains, ranging from amino acid residues 1-252 and 253-371, respectively. The P-domain assembles into dimeric protruding spikes, and it is believed to be involved in host cell attachment and internalization. In this study, the recombinant P-domain of MrNV-CP was successfully cloned and expressed in Escherichia coli, purified with an immobilized metal affinity chromatography (IMAC) and size exclusion chromatography (SEC) up to ~90% purity. Characterization of the purified recombinant P-domain with SEC revealed that it formed dimers, and dynamic light scattering (DLS) analysis demonstrated that the hydrodynamic diameter of the dimers was ~6 nm. Circular dichroism (CD) analysis showed that the P-domain contained 67.9% of beta-sheets, but without alpha-helical structures. This is in good agreement with the cryo-electron microscopic analysis of MrNV which demonstrated that the P-domain contains only beta-stranded structures. Our findings of this study provide essential information for the production of the P-domain of MrNV-CP that will aid future studies particularly studies that will shed light on anti-viral drug discovery and provide an understanding of virus-host interactions and the viral pathogenicity.
    Matched MeSH terms: Chromatography, Gel
  2. IgA binding lectins isolated from distinct Artocarpus species demonstrate differential specificity
    Hashim OH, Ng CL, Gendeh S, Nik Jaafar MI
    Mol Immunol, 1991 4 1;28(4-5):393-8.
    PMID: 2062319
    The discovery of jacalin, a group of lectins from jackfruit seeds (Artocarpus heterophyllus), has attracted considerable attention due to its numerous interesting immunological properties as well as its usefulness in the isolation of various serum proteins. We have further identified a similar lectin from the seeds of Champedak (Artocarpus integer) which we refer to as lectin-C and performed comparative studies with two types of jacalin isolated from different batches of the Malaysian jackfruit seeds (jacalin-M1 and jacalin-M2). The three purified lectins demonstrated equivalent apparent Mr of about 52,500, each of which comprised of a combination of two types of non-covalently-linked subunits with apparent Mr of approximately 13,300 and 16,000. The lectins demonstrated equal haemagglutinating activity against human erythrocytes of blood groups A, B, AB and O. Our data also demonstrated that lectin-C, jacalin-M1 and jacalin-M2 are similar by selectively precipitating human serum IgA1 and colostral sIgA but not IgA2, IgD, IgG and IgM. When immunoelectrophoresis was performed on normal human sera and reacted with the lectins, single precipitin arcs corresponding to IgA immunoprecipitates were detected with lectin-C and jacalin-MI. Jacalin-M2, however, exhibited two closely associated precipitin arcs. The binding of these lectins with IgA was pronouncedly inhibited in the presence of p-nitrophenyl-beta-D-galactopyranoside, 1-o-methyl-alpha-D-galactopyranoside, D-melibiose, N-acetyl-D-galactosamine and D-galactose. The data therefore provide evidence on the differential specificity of IgA binding lectins isolated from seeds of similar as well as distinct Artocarpus species.
    Matched MeSH terms: Chromatography, Gel
  3. Purification and characterization of 31-kDa palm pollen glycoprotein (Ela g Bd 31 K), which is recognized by IgE from palm pollinosis patients
    Kimura Y, Maeda M, Kimupa M, Lai OM, Tan SH, Hon SM, et al.
    Biosci Biotechnol Biochem, 2002 Apr;66(4):820-7.
    PMID: 12036055
    A basic glycoprotein, which was recognized by IgE from oil palm pollinosis patients, has been purified from oil palm pollen (Elaeis guineensis Jacq.), which is a strong allergen and causes severe pollinosis in Malaysia and Singapore. Soluble proteins were extracted from defatted palm pollen with both Tris-HCl buffer (pH 7.8) and Na-acetate buffer (pH 4.0). The allergenic glycoprotein was purified from the total extract to homogeneity with 0.4% yield by a combination of DEAE- and CM-cellulose, SP-HPLC, and gel filtration. The purified oil palm pollen glycoprotein with molecular mass of 31 kDa was recognized by the beta1-2 xylose specific antibody, suggesting this basic glycoprotein bears plant complex type N-glycan(s). The palm pollen basic glycoprotein, designated Ela g Bd 31 K, was recognized by IgE of palm pollinosis patients, suggesting Ela g Bd 31 K should be one of the palm pollen allergens. The preliminary structural analysis of N-glycans linked to glycoproteins of palm pollens showed that the antigenic N-glycans having alpha1-3 fucose and alpha1-2 xylose residues (GlcNAc(2 to approximately 0)Man3Xyl1Fuc(1 to approximately 0)GlcNAc2) actually occur on the palm pollen glycoproteins, in addition to the high-mannose type structures (Man(9 to approximately 5)GlcNAc2).
    Matched MeSH terms: Chromatography, Gel
  4. Isolation and characterization of a hemorrhagin from the venom of Ophiophagus hannah (king cobra)
    Tan NH, Saifuddin MN
    Toxicon, 1990;28(4):385-92.
    PMID: 2190359
    The major hemorrhagin (termed hannahtoxin) of the venom of Ophiophagus hannah (king cobra) was purified to electrophoretic homogeneity by DEAE-Sephacel ion exchange chromatography, Sephadex G-200 gel filtration followed by a second DEAE-Sephacel chromatography. Proteolytic activity was associated with the hemorrhagic activity throughout the purification procedures. Hannahtoxin constituted approximately 2% of the crude venom. It had an isoelectric point of 5.3, a carbohydrate content of 12%, a mol. wt of 66,000 as determined by SDS-polyacrylamide gel electrophoresis and 63,000 as determined by gel filtration. It contains 1 mole of Zn per mole of protein. The minimum hemorrhage doses for hannahtoxin are 0.7 microgram and 75 micrograms, respectively, in rabbits and in mice. Hannahtoxin was not lethal to mice at a dose of 2 mg/kg (i.v.) but killed rabbits at doses above 0.18 mg/kg (i.v.). It liberated protein from rabbit glomerular basement membrane but not rat glomerular basement membrane. Treatment of the hemorrhagin with EDTA and 1,10-phenanthroline eliminated both the proteolytic and hemorrhagic activities completely.
    Matched MeSH terms: Chromatography, Gel
  5. The use of enzyme-linked immunosorbent assay for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom and venom antibodies
    Tan NH, Yeo KH, Jaafar MI
    Toxicon, 1992 Dec;30(12):1609-20.
    PMID: 1488770
    The specificity and sensitivity of an indirect and two (an 'ordinary' and a 'rapid') double sandwich enzyme-linked immunosorbent assay (ELISA) procedures for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom were examined. The three assays were equally sensitive and the accuracy of the assays was not substantially affected by individual variation in the venom composition. The specificity of the assays was examined against 26 venoms from snakes of the families Viperidae and Elapidae. While the double sandwich ELISA procedures were sufficiently specific to be used in the clinical immunodiagnosis of C. rhodostoma bite in Malaysia, the indirect ELISA procedure exhibited extensive cross-reactivity with other Malaysian pit viper venoms. Attempts were made to improve the specificity of the indirect ELISA procedure for the quantitation of C. rhodostoma venom. A 'low ELISA cross-reactivity' venom fraction (termed VF52) was isolated from C. rhodostoma venom by repeated Sephadex G-100 gel filtration chromatography. The indirect ELISA procedure using antibodies to VF52 as immunoreagent showed an improvement in specificity. The use of the indirect ELISA procedure for the detection of C. rhodostoma antibodies was also examined and the results show that the assay was sufficiently specific to be used for retrospective diagnosis of C. rhodostoma bite in Malaysia, in particular when VF52 was used as the coating antigen.
    Matched MeSH terms: Chromatography, Gel
  6. Fulltext Protein identification of vitellogenin in river catfish (Hemibagrus nemurus)
    Roshani Othman, Sharr Azni Harmin, Ina-Salwany Md Yasin
    Bioremediation Science and Technology Research, 2015;3(1):1-5.
    MyJurnal
    Mass production of fish broodstock with high quality eggs requires the knowledge on the chemical composition and physiochemical properties of vitellogenin (Vtg) during ovulation. Vtg is an egg yolk precursor phospholipoglycoprotein, and has been analysed to evaluate the reproductive conditions and determine the spawning period in captive and wild fish. In this study, Vtg was induced in male H. nemurus through three intramuscular injections of 17-estradiol (E2). The Vtg was purified from the serum using gel filtration chromatography and the purified protein was reduced via SDS-PAGE. One major polypeptide corresponding to 130 kDa was observed. Vtg identification was done using peptide mass fingerprint (PMF) from the trypsin digestion of male H. nemurus Vtg induced with E2. The sequence homology of H. nemurus AYLAGAAADVLEVGVR matched the Vtg of other fish species when analysed using MALDI-TOF. Vtg was confirmed by MASCOT at 95% significant level. The potential protein that controls the reproductive process and oocyte development isolated from this study was discussed to understand the structure and function of Vtg.
    Matched MeSH terms: Chromatography, Gel
  7. Production of uv-curable palm oil resins/oligomers using laboratory scale and pilot scale systems
    Rida Tajau, Mohd hilmi Mahmood, Mek Zah Salleh, Khairul Zaman Mohd dahlan, Rosley Che ismail, Sharilla Muhammad Faisal, et al.
    Sains Malaysiana, 2013;42:459-467.
    In recent years, there are growing trends in using palm oil as raw materials in radiation curable resins production. In this study, the acrylated palm oil resins i.e. the EPOLA (epoxidized palm oil acrylate) and the POBUA (palm oil based urethane acrylate) were synthesized using two different systems, i.e. the 25 liter pilot scale reactor synthesis system and the 2 liter (L) laboratory scale reactor synthesis system through chemical processes known as acrylation and isocyanation. In this
    paper, the property of the acrylated resins which were produced by these two systems were evaluated and compared between each other. Their properties were characterized using the Fourier transform infrared (FTIR) spectrophotometer for functional group identification; the gel permeation chromatography (GPC) for molecular weight (Mw) determination, the Brookfield viscometer for viscosity measurements, the acid values (AV) and the oxirane oxygen contents (OOC) analysis. As a result, the production process for both the 2 L and 25 L reactor system were found to be time consuming and the main advantages for the 25 L reactor was its higher productivity as compared with the 2 L reactor system with the same synthesis process parameters i.e. the temperatures and the experimental methods. Besides that, the 25 L reactor synthesis
    process was found to be safe, easy to control and served unpolluted process to the environments. The final products, the acrylated palm oil resins were formulated into ultraviolet (UV) curable compounds before subjecting them under UVirradiation. As a result, the UV-curable palm oil resins showed potential uses as pressure sensitive adhesives, printing inks including overprint varnishes (OPV) and coatings.
    Matched MeSH terms: Chromatography, Gel
  8. A validated size exclusion chromatography method coupled with fluorescence detection for rapid quantification of bevacizumab in ophthalmic formulations
    Jirjees F, Soliman K, Wang Y, Sonawane R, Sheshala R, Jones D, et al.
    J Pharm Biomed Anal, 2019 Sep 10;174:145-150.
    PMID: 31167158 DOI: 10.1016/j.jpba.2019.05.038
    Bevacizumab is a full-length human monoclonal antibody used to treat various neovascular diseases such as wet age-related macular degeneration (AMD), diabetic eye disease and other problems of the retina. Monthly intravitreal injections of bevacizumab (Avastin®) are effective in the treatment of wet AMD. However, there is a growing demand in the development of sustained release ophthalmic formulations. Therefore, this study aims, for the first time, to develop a rapid, simple, and sensitive method using size exclusion chromatography coupled with fluorescence detection for routine quantification of bevacizumab in ophthalmic formulations and during in vitro release studies. The selected chromatographic conditions included an aqueous mobile phase composed of 35 mM sodium phosphate buffer and 300 mM sodium chloride (pH 6.8), a flow rate of 0.5 mL/min, and the fluorescence detector was operated at excitation and emission wavelengths of 280 and 340 nm, respectively. The peak area-concentration relationship maintained its linearity over concentration range of 0.1-20 μg/mL (R2 = 0.9993), and the quantitation limit was 100 ng/mL. The method was validated for specificity, accuracy, precision, and robustness. The developed method had a run time of 6 min at temperature 25 °C, making it a unique validated method for rapid and cost-effective quantification of bevacizumab.
    Matched MeSH terms: Chromatography, Gel
  9. Isolation, characterization and antigenic cross-reactivities of the major hemorrhagin from Cryptelytrops purpureomaculatus venom
    Fung SY, Tan NH
    Indian J Exp Biol, 2013 Dec;51(12):1063-9.
    PMID: 24579371
    The major hemorrhagin from C. purpureomaculatus (mangrove pit viper) venom was purified to homogeneity and termed Maculatoxin. Maculatoxin has a molecular weight of 38 kDa as determined by SDS-PAGE. It is an acidic protein (pI= 4.2) and exhibited proteolytic and hemorrhagic activities (MHD10 = 0.84 microg in mice) but was not lethal to mice at a dose of 1 microg/g. The hemorrhagic activity of Maculatoxin was completely inactivated by EDTA and partially inhibited by ATP and citrate. The N-terminal sequence of Maculatoxin (TPEQQRFPPTYIDLGIFVDHGMYAT) shares a significant degree of homology with the metalloprotease domain of other venom hemorrhagins. Indirect ELISA showed anti-Maculatoxin cross reacted with protein components of many snake venoms. In the double-sandwich ELISA, however, anti-Maculatoxin cross-reacted only with venoms of certain species of the Trimeresurus (Asia lance-head viper) complex, and the results support the recent proposed taxonomy changes concerning the Trimeresurus complex.
    Matched MeSH terms: Chromatography, Gel
  10. Fulltext Chemical composition and molecular structure of polysaccharide-protein biopolymer from Durio zibethinus seed: extraction and purification process
    Amid BT, Mirhosseini H, Kostadinović S
    Chem Cent J, 2012 Oct 14;6(1):117.
    PMID: 23062269 DOI: 10.1186/1752-153X-6-117
    BACKGROUND: The biological functions of natural biopolymers from plant sources depend on their chemical composition and molecular structure. In addition, the extraction and further processing conditions significantly influence the chemical and molecular structure of the plant biopolymer. The main objective of the present study was to characterize the chemical and molecular structure of a natural biopolymer from Durio zibethinus seed. A size-exclusion chromatography coupled to multi angle laser light-scattering (SEC-MALS) was applied to analyze the molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (Mw/Mn).

    RESULTS: The most abundant monosaccharide in the carbohydrate composition of durian seed gum were galactose (48.6-59.9%), glucose (37.1-45.1%), arabinose (0.58-3.41%), and xylose (0.3-3.21%). The predominant fatty acid of the lipid fraction from the durian seed gum were palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:2). The most abundant amino acids of durian seed gum were: leucine (30.9-37.3%), lysine (6.04-8.36%), aspartic acid (6.10-7.19%), glycine (6.07-7.42%), alanine (5.24-6.14%), glutamic acid (5.57-7.09%), valine (4.5-5.50%), proline (3.87-4.81%), serine (4.39-5.18%), threonine (3.44-6.50%), isoleucine (3.30-4.07%), and phenylalanine (3.11-9.04%).

    CONCLUSION: The presence of essential amino acids in the chemical structure of durian seed gum reinforces its nutritional value.

    Matched MeSH terms: Chromatography, Gel
  11. Processing of polycaprolactone and polycaprolactone-based copolymers into 3D scaffolds, and their cellular responses
    Hoque ME, San WY, Wei F, Li S, Huang MH, Vert M, et al.
    Tissue Eng Part A, 2009 Oct;15(10):3013-24.
    PMID: 19331580 DOI: 10.1089/ten.TEA.2008.0355
    Synthetic polymers have attracted much attention in tissue engineering due to their ability to modulate biomechanical properties. This study investigated the feasibility of processing poly(epsilon-caprolactone) (PCL) homopolymer, PCL-poly(ethylene glycol) (PEG) diblock, and PCL-PEG-PCL triblock copolymers into three-dimensional porous scaffolds. Properties of the various polymers were investigated by dynamic thermal analysis. The scaffolds were manufactured using the desktop robot-based rapid prototyping technique. Gross morphology and internal three-dimensional structure of scaffolds were identified by scanning electron microscopy and micro-computed tomography, which showed excellent fusion at the filament junctions, high uniformity, and complete interconnectivity of pore networks. The influences of process parameters on scaffolds' morphological and mechanical characteristics were studied. Data confirmed that the process parameters directly influenced the pore size, porosity, and, consequently, the mechanical properties of the scaffolds. The in vitro cell culture study was performed to investigate the influence of polymer nature and scaffold architecture on the adhesion of the cells onto the scaffolds using rabbit smooth muscle cells. Light, scanning electron, and confocal laser microscopy showed cell adhesion, proliferation, and extracellular matrix formation on the surface as well as inside the structure of both scaffold groups. The completely interconnected and highly regular honeycomb-like pore morphology supported bridging of the pores via cell-to-cell contact as well as production of extracellular matrix at later time points. The results indicated that the incorporation of hydrophilic PEG into hydrophobic PCL enhanced the overall hydrophilicity and cell culture performance of PCL-PEG copolymer. However, the scaffold architecture did not significantly influence the cell culture performance in this study.
    Matched MeSH terms: Chromatography, Gel
  12. Fulltext Cloning, expression, purification, crystallization and X-ray crystallographic analysis of recombinant human C1ORF123 protein
    Rahaman SN, Mat Yusop J, Mohamed-Hussein ZA, Ho KL, Teh AH, Waterman J, et al.
    Acta Crystallogr F Struct Biol Commun, 2016 Mar;72(Pt 3):207-13.
    PMID: 26919524 DOI: 10.1107/S2053230X16002016
    C1ORF123 is a human hypothetical protein found in open reading frame 123 of chromosome 1. The protein belongs to the DUF866 protein family comprising eukaryote-conserved proteins with unknown function. Recent proteomic and bioinformatic analyses identified the presence of C1ORF123 in brain, frontal cortex and synapses, as well as its involvement in endocrine function and polycystic ovary syndrome (PCOS), indicating the importance of its biological role. In order to provide a better understanding of the biological function of the human C1ORF123 protein, the characterization and analysis of recombinant C1ORF123 (rC1ORF123), including overexpression and purification, verification by mass spectrometry and a Western blot using anti-C1ORF123 antibodies, crystallization and X-ray diffraction analysis of the protein crystals, are reported here. The rC1ORF123 protein was crystallized by the hanging-drop vapor-diffusion method with a reservoir solution comprised of 20% PEG 3350, 0.2 M magnesium chloride hexahydrate, 0.1 M sodium citrate pH 6.5. The crystals diffracted to 1.9 Å resolution and belonged to an orthorhombic space group with unit-cell parameters a = 59.32, b = 65.35, c = 95.05 Å. The calculated Matthews coefficient (VM) value of 2.27 Å(3) Da(-1) suggests that there are two molecules per asymmetric unit, with an estimated solvent content of 45.7%.
    Matched MeSH terms: Chromatography, Gel
  13. Purification and properties of the L-amino acid oxidase from Malayan pit viper (Calloselasma rhodostoma) venom
    Ponnudurai G, Chung MC, Tan NH
    Arch Biochem Biophys, 1994 Sep;313(2):373-8.
    PMID: 8080286
    The L-amino acid oxidase of Malayan pit viper (Calloselasma rhodostoma) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 132,000 as determined by Sephadex G-200 gel filtration chromatography and 66,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is a glycoprotein, has an isoelectric point of 4.4, and contains 2 mol of flavin mononucleotide per mole of enzyme. The N-terminal amino acid sequence of the enzyme was A-D-D-R-N-P-L-A-E-E-F-Q-E-N-N-Y-E-E-F-L. Kinetic studies suggest the presence of a alkyl side-chain binding site in the enzyme and that the binding site comprises at least four hydrophobic subsites. The characteristics of the binding site differ slightly from those of cobra venom L-amino acid oxidases.
    Matched MeSH terms: Chromatography, Gel
  14. Purification and characterization of two acidic phospholipase A2 enzymes from king cobra (Ophiophagus hannah) snake venom
    Tan NH, Saifuddin MN
    Int. J. Biochem., 1990;22(5):481-7.
    PMID: 2347427
    1. The two major phospholipase A2 enzymes (OHPLA-DE1 and OHPLA-DE2) of king cobra (Ophiophagus hannah) venom have been purified to electrophoretic homogeneity. 2. The isoelectric points of OHPLA-DE1 and OHPLA-DE2 were 3.81 and 3.89, respectively and the Mws were 14,000 and 15,000, respectively, as estimated by Sephadex G-75 gel filtration chromatography; and 14,000 as estimated by SDS-PAGE. 3. The enzymes were not lethal to mice at a dosage of 10 micrograms/g body wt by i.v. route. Both phospholipase A2 enzymes, however, exhibited moderate edema-inducing and anti-coagulant activities. 4. Bromophenacylation of the enzymes reduced the enzymatic activity drastically but did not affect the edema-inducing activity of the enzymes.
    Matched MeSH terms: Chromatography, Gel
  15. A comparative study of the biological properties of venoms from snakes of the genus Vipera (true adders)
    Tan NH, Ponnudurai G
    Comp. Biochem. Physiol., B, 1990;96(4):683-8.
    PMID: 2171867
    1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, hyaluronidase, alkaline phosphomonoesterase, 5'-nucleotidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 26 samples of venoms of 13 taxa of Vipera were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. The results indicate the presence of certain common characteristics among the venoms, particularly if V. russelli is excluded from the comparison. The results also support the recently proposed reassignment of V. russelli to a separate genus. 3. The data show that information on venom biological properties can be used for differentiation of venoms of many species of Vipera. Particularly useful for this purpose are the protease, phosphodiesterase, phospholipase A and the procoagulant activities and the Sephadex G-75 gel filtration patterns of the venoms.
    Matched MeSH terms: Chromatography, Gel
  16. Does recovery in the spectral characteristics of GdnHCl-denatured Bacillus licheniformis α-amylase due to added calcium point towards protein stabilization?
    Halim AA, Feroz SR, Tayyab S
    Biosci Biotechnol Biochem, 2013;77(1):87-96.
    PMID: 23291750
    Treatment of Bacillus licheniformis α-amylase (BLA) with guanidine hydrochloride (GdnHCl) produced both denatured and aggregated forms of the enzyme as studied by circular dichroism, fluorescence, UV difference spectroscopy, size exclusion chromatography (SEC), and enzymatic activity. The presence of CaCl(2) in the incubation mixture produced significant recovery in spectral signals, being complete in presence of 10 mM CaCl(2), as well as in enzymatic activity, which is indicative of protein stabilization. However, the SEC results obtained with GdnHCl-denatured BLA both in the absence and the presence of 10 mM CaCl(2) suggested significant aggregation of the protein in the absence of CaCl(2) and disaggregation in its presence. Although partial structural stabilization with significant retention of enzymatic activity was observed in the presence of calcium, it was far from the native state, as reflected by spectral probes. Hence, spectral results as to BLA stabilization should be treated with caution in the presence of aggregation.
    Matched MeSH terms: Chromatography, Gel
  17. Purification and properties of two forms of glucoamylase from Aspergillus niger
    Amirul AA, Khoo SL, Nazalan MN, Razip MS, Azizan MN
    Folia Microbiol (Praha), 1996;41(2):165-74.
    PMID: 9138312
    A. niger produced alpha-glucosidase, alpha-amylase and two forms of glucoamylase when grown in a liquid medium containing raw tapioca starch as the carbon source. The glucoamylases, which formed the dominant components of amylolytic activity manifested by the organism, were purified to homogeneity by ammonium sulfate precipitation, ion-exchange and two cycles of gel filtration chromatography. The purified enzymes, designated GA1 and GA2, a raw starch digesting glucoamylase, were found to have molar masses of 74 and 96 kDa and isoelectric points of 3.8 and 3.95, respectively. The enzymes were found to have pH optimum of 4.2 and 4.5 for GA1 and GA2, respectively, and were both stable in a pH range of 3.5-9.0. Both enzymes were thermophilic in nature with temperature optimum of 60 and 65 degrees C, respectively, and were stable for 1 h at temperatures of up to 60 degrees C. The kinetic parameters Km and V showed that with both enzymes the branched substrates, starch and amylopectin, were more efficiently hydrolyzed compared to amylose. GA2, the more active of the two glucoamylases produced, was approximately six to thirteen times more active towards raw starches compared to GA1.
    Matched MeSH terms: Chromatography, Gel
  18. Fractionation and Biological Activities of Water-Soluble Polysaccharides from Sclerotium of Tiger Milk Medicinal Mushroom, Lignosus rhinocerotis (Agaricomycetes)
    Keong CY, B V, Daker M, Hamzah MY, Mohamad SA, Lan J, et al.
    Int J Med Mushrooms, 2016;18(2):141-54.
    PMID: 27279536 DOI: 10.1615/IntJMedMushrooms.v18.i2.50
    This study investigated antioxidant and anti-inflammatory properties, and the direct cytotoxic effect of Lignosus rhinocerotis fractions, especially the polysaccharide fraction, on nasopharyngeal carcinoma cells. L. rhinocerotis crude extract was obtained through hot water extraction. The precipitate saturated with 30% ammonium sulfate was purified with ion-exchanged chromatography. Gel permeation chromatography multiangle laser light scattering analysis equipped with light scattering and UV signals revealed two district groups of polymers. A total of four peaks were observed in the total carbohydrate test. Fraction C, which was the second region of the second peak eluted with 0.3 M NaOH, showed the highest integrated molecular weight, whereas fraction E had the lowest integrated molecular weight of 19,790 Da. Fraction A contained the highest β-D-glucan content. Enzymatic analysis showed that most of the polysaccharide fractions contained β-1-3 and β-1-6 skeletal backbones. The peak eluted with 0.6 M NaOH was separated in fraction D (flask 89-92) and fraction E (93-96). The results showed that fraction E expressed higher antioxidant activities than fraction D whereas fraction D expressed higher chelating activity than fraction E. The extract saturated with 30% ammonium sulfate exhibited higher reducing power than the extract saturated with 100% ammonium sulfate. Fractions D and E significantly inhibited the secretion of tumor necrosis factor-α in lipopolysaccharide-stimulated RAW 264.7 macrophages in a dose-dependent manner. There was no apparent difference in the viability of cells exposed or unexposed to L. rhinocerotis fractions.
    Matched MeSH terms: Chromatography, Gel
  19. Fulltext Molecular characterization of a recombinant manganese superoxide dismutase from Lactococcus lactis M4
    Tan BH, Chor Leow T, Foo HL, Abdul Rahim R
    Biomed Res Int, 2014;2014:469298.
    PMID: 24592392 DOI: 10.1155/2014/469298
    A superoxide dismutase (SOD) gene of Lactococcus lactis M4 was cloned and expressed in a prokaryotic system. Sequence analysis revealed an open reading frame of 621 bp which codes for 206 amino acid residues. Expression of sodA under T7 promoter exhibited a specific activity of 4967 U/mg when induced with 1 mM of isopropyl-β-D-thiogalactopyranoside. The recombinant SOD was purified to homogeneity by immobilised metal affinity chromatography and Superose 12 gel filtration chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot analyses of the recombinant SOD detected a molecular mass of approximately 27 kDa. However, the SOD was in dimer form as revealed by gel filtration chromatography. The purified recombinant enzyme had a pI of 4.5 and exhibited maximal activity at 25°C and pH 7.2. It was stable up to 45°C. The insensitivity of this lactococcal SOD to cyanide and hydrogen peroxide established that it was a MnSOD. Although it has 98% homology to SOD of L. lactis IL1403, this is the first elucidated structure of lactococcal SOD revealing active sites containing the catalytic manganese coordinated by four ligands (H-27, H-82, D-168, and H-172).
    Matched MeSH terms: Chromatography, Gel
  20. Structure-activity relationship of polyisoprenyl benzophenones from Garcinia pyrifera on the tubulin/microtubule system
    Roux D, Hadi HA, Thoret S, Guénard D, Thoison O, Païs M, et al.
    J Nat Prod, 2000 Aug;63(8):1070-6.
    PMID: 10978200
    Microtubule disassembly inhibitory properties have been established for the known polyisoprenylated benzophenones xanthochymol (1a) and guttiferone E (1b). The compounds were isolated from the fruits of Garcinia pyrifera collected in Malaysia. A structure-activity relationship study, including natural and semisynthetic derivatives, delineated some structural features necessary for the interaction with tubulin within this compound class.
    Matched MeSH terms: Chromatography, Gel
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links