Displaying publications 1 - 20 of 77 in total

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  1. Structural identification of haemoglobin F Kuala Lumpur: alpha2 gamma2 22(B4)Asp leads to Gly; 136 Ala
    Luan Eng LI, Wiltshire BG, Lehmann H
    Biochim. Biophys. Acta, 1973 Oct 18;322(2):224-30.
    PMID: 4765089
    Matched MeSH terms: Chromatography, Ion Exchange
  2. Enzymatic activities of Malayan cobra (Naja naja sputatrix) venoms
    Tan NH, Tan CS
    Toxicon, 1987;25(11):1249-53.
    PMID: 3433296
    The enzymatic activities of four samples of Malayan cobra venom were investigated. There was significant variation in the contents of L-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase A, 5'-nucleotidase and hyaluronidase. The phosphodiesterase content was, however, constant. Storage of the lyophilized venom powder at 25 degrees C for 1 month did not affect the enzymatic activities. The venom enzymatic activities were generally also stable at 4 degrees C in 0.85% saline solution. After incubation at 37 degrees C for 39 days in 0.85% saline solution, the venom still retained considerable amounts of enzymatic activities. SP-Sephadex C-25 ion-exchange chromatography of the venom showed that the phospholipase A, L-amino acid oxidase, 5'-nucleotidase, phosphodiesterase and alkaline phosphomonoesterase exist in multiple forms.
    Matched MeSH terms: Chromatography, Ion Exchange
  3. Fulltext Investigations on the relative synthesis of globin chains in thalassaemia: a preliminary study in Malaysian subjects
    Hassan K, Vijayasilan T, Mahmood Z, Abdul Hamid H, Chin YM
    Singapore Med J, 1988 Oct;29(5):462-8.
    PMID: 3241975
    Whole blood samples from patients with various forms of alpha- and beta- thalassaemia were incubated with 14C-Leucine to determine the relative rates of production of the alpha and beta chains by their reticulocytes. The labelled globin chains were fractionated by CM-Cellulose Chromatography in 8M Urea and the incorporated activity determined. The relative rates of synthesis of alpha and beta chains in some cases of alpha and beta- thalassaemia were established and the chain synthetic ratios were compared with similar ratios in normal individuals. The results show that it is possible to identify from the relative rates of in-vitro synthesis of the alpha and beta chains, the presence of the common thalassaemia slates in particular beta-thal trait, beta-thal homozygotes, Hb H disease and alpha0-thal trait. The presence of transfused blood does not affect the result. This study indicates that an abnormal alpha/beta chain synthesis ratio is useful in defining alpha and beta-thalassaemia variants.
    Matched MeSH terms: Chromatography, Ion Exchange
  4. Biological properties of Trimeresurus purpureomaculatus (shore pit viper) venom and its fractions
    Nget Hong Tan, Chon Seng Tan
    Toxicon, 1988;26(11):989-96.
    PMID: 3245058
    The toxic and biological activities of four samples of Trimeresurus purpureomaculatus venom were examined. The lethality, protein composition and biological activities of the four venom samples were similar. Three of the venom samples had LD50 (i.v.) values of 0.9 micrograms/g while the fourth had a lower LD50 (i.v.) of 0.45 micrograms/g. All four venom samples exhibited hemorrhagic, edema-inducing, anticoagulant and thrombin-like activities as well as the usual enzymes found in crotalid venoms. DEAE-Sephacel ion exchange chromatographic fractionation of the venom yielded 10 protein fractions. Only two fractions (fractions A and F) were lethal to mice; the major lethal fraction being fraction F. This fraction had an LD50 (i.v.) of 0.2 micrograms/g and exhibited hemorrhagic, edema-inducing and thrombin-like activity. It also exhibited phospholipase A, arginine ester hydrolase, arginine amidase, protease, 5'-nucleotidase, acetylcholinesterase and alkaline phosphomonoesterase activities. The lethal potency of fraction F is potentiated by fraction G, which exhibited anticoagulant activity as well as hemorrhagic, edema-inducing and enzymatic activities. Fractions F plus G account for almost 100% of the lethal potency of the venom.
    Matched MeSH terms: Chromatography, Ion Exchange
  5. Isolation and characterization of an acidic lethal phospholipase Az from Malayan cobra (Naja naja sputatrix) venom
    Tan NH, Arunmozhiarasi A
    Biochem. Int., 1989 Apr;18(4):785-92.
    PMID: 2764979
    An acidic, lethal phospholipase Az was purified to electrophoretic homogeneity from the venom of the Malayan cobra (Naja naja sputatrix). The enzyme has an isoelectric point of 5.58, a molecular weight of 12000, and a medium lethal dose (LD50) of 0.86 micrograms/g in mice by intravenous injection. The enzyme also exhibited weak anticoagulant and edema-forming activities. The amino acid composition of the enzyme is similar to those of other cobra venom phospholipases Az.
    Matched MeSH terms: Chromatography, Ion Exchange
  6. Isolation and characterization of an unusual form of L-amino acid oxidase from King cobra (Ophiophagus hannah) venom
    Tan NH, Saifuddin MN
    Biochem. Int., 1989 Oct;19(4):937-44.
    PMID: 2619759
    The L-amino acid oxidase (EC 1. 4. 3. 2) from King cobra (Ophiophagus hannah) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was determined to be 140000 when examined by gel filtration and 68000 by SDS-polyacrylamide gel electrophoresis. The enzyme had an isoelectric point of 4.5 and an intravenous LD50 of 5 micrograms/g in mice. It is a glycoprotein and contains two moles of FAD per mole of enzyme. The enzyme exhibited unusual thermal stability and unlike most other venom L-amino acid oxidases, it was stable in alkaline solution and was not inactivated by freezing.
    Matched MeSH terms: Chromatography, Ion Exchange
  7. The enzymatic activities and lethal toxins of Trimeresurus wagleri (speckled pit viper) venom
    Tan NH, Tan CS
    Toxicon, 1989;27(3):349-57.
    PMID: 2543103
    Trimeresurus wagleri (speckled pit viper) venom exhibited the usual set of enzyme activities occurring in pit viper venoms but the content of alkaline phosphomonoesterase was unusually high, whereas the proportions of protease and arginine ester hydrolase were very low. The venom also exhibited weak thrombin-like activity but did not exhibit hemorrhagic or anticoagulant activity. Analysis of the Sephadex G-200 gel filtration fractions of the venom indicated that the lethal fraction was a low mol.wt protein, and that fractions exhibiting phosphodiesterase, phosphomonoesterase, arginine ester hydrolase, thrombin-like enzyme, L-amino acid oxidase and phospholipase A activities were not lethal. Two lethal toxins, designated as wagleri toxins 1 and 2, were isolated from the venom using Sephadex G-50 gel filtration chromatography followed by SP-Sephadex C-25 ion exchange chromatography. The mol.wts of the two toxins were 8900 by gel filtration. The LD50 (i.v.) values in mice for wagleri toxins 1 and 2 are 0.17 microgram/g and 0.19 microgram/g, respectively.
    Matched MeSH terms: Chromatography, Ion Exchange
  8. The lethal and biochemical properties of Bungarus candidus (Malayan krait) venom and venom fractions
    Tan NH, Poh CH, Tan CS
    Toxicon, 1989;27(9):1065-70.
    PMID: 2799837
    Bungarus candidus venom exhibited high hyaluronidase, acetylcholinesterase and phospholipase A activities; low proteinase, 5'-nucleotidase, alkaline phosphomonoesterase and phosphodiesterase activities and moderately high L-amino acid oxidase activity. SP-Sephadex C-50 ion exchange chromatographic fractionation of the venom and Sephadex G-50 chromatography of the major lethal venom fractions indicate that the venom contains at least two highly lethal, basic phospholipases A with LD50 (i.v.) values of 0.02 micrograms/g (F6A) and 0.18 micrograms/g (F4A), respectively; as well as two polypeptide toxins with LD50 (i.v.) values of 0.17 micrograms/g and 0.83 micrograms/g, respectively. The major lethal toxin is the basic lethal phospholipase A, F6A, which accounts for approximately 13% of the venom protein and has a mol. wt of 21,000.
    Matched MeSH terms: Chromatography, Ion Exchange
  9. Fractionation of Sumatran pit viper (Trimeresurus sumatranus sumatranus) venom by DEAE-Sephacel ion exchange chromatography and some biological properties of the fractions
    Tan NH, Tan CS
    Toxicon, 1989;27(6):697-702.
    PMID: 2749766
    Sumatran pit viper (Trimeresurus sumatranus sumatranus) venom was fractionated by DEAE-Sephacel ion exchange chromatography into seven fractions. Fractions 4, 5 and 6 were lethal to mice and exhibited strong hemorrhagic activity, as well as some enzymatic activities. Fraction 6 also exhibited potent anticoagulant and thrombin-like activities. Analysis of the biological and enzymatic properties of the three lethal fractions suggests that the major lethal component of fractions 4 and 5 may be the hemorrhagic principle, and that the lethality of fraction 6 may be due to the hemorrhagic principle and/or the anticoagulant principle.
    Matched MeSH terms: Chromatography, Ion Exchange
  10. Assay of 3-hydroxy-3-methylglutaryl CoA reductase activity using anionic-exchange column chromatography
    Ong KK, Khor HT, Tan DT
    Anal Biochem, 1991 Aug 01;196(2):211-4.
    PMID: 1776669
    A rapid, easy, and sensitive method is described in this paper for the assay of 3-hydroxy-3-methylglutaryl CoA (HMG CoA) reductase, a key enzyme in cholesterol biosynthesis. [14C]HMG CoA was used as the substrate and the product formed, i.e., [14C]mevalonate, was allowed to be converted to its lactone form (mevalonolactone) in the presence of HCl. The reaction mixture was applied to a column containing an anionic exchanger. The column was made up of QAE-Sephadex (A25, formate form) packed to a height of 4 cm in Pasteur pipets. Under these conditions, mevalonolactone was not retained by the column and was eluted with ammonium formate solution while HMG CoA, being negatively charged, was retained by the gel and eluted by HCl above 0.05 M. Determination of the amount of radioactivity in mevalonolactone was then used to quantitate the activity of HMG CoA reductase. This assay has been successfully used for determining the activity of this enzyme in a microsomal fraction prepared from the liver of the rat.
    Matched MeSH terms: Chromatography, Ion Exchange/methods*
  11. Haemolytic, oedema and haemorrhage inducing activities of tentacular extract of the blubber jellyfish (Catostylus mosaicus)
    Azila N, Siao FK, Othman I
    Comp Biochem Physiol C Comp Pharmacol Toxicol, 1991;99(1-2):153-6.
    PMID: 1675964
    1. An extract prepared from the tentacle of the jellyfish (CE), Catostylus mosaicus exhibited haemolytic, oedema and haemorrhage-inducing activities. 2. Acetone treatment of the tentacle extract produced an acetone soluble extract (AE) which showed an increase in specific haemolytic and haemorrhagic activities by 25- and 120-fold respectively; the minimum oedema dose was reduced by 30-fold. 3. The AE caused a rapid onset of oedema in the mouse foot pad. The effect was long-lasting, reaching a maximum in about 30 min after injection and sustained up to 4 hr. 4. Fractionation of the AE on Q-Sepharose gave 4 bound fractions which induced oedema and haemorrhage; however only 3 of the fractions exhibited haemolytic activity.
    Matched MeSH terms: Chromatography, Ion Exchange
  12. Purification and properties of the L-amino acid oxidase from monocellate cobra (Naja naja kaouthia) venom
    Tan NH, Swaminathan S
    Int. J. Biochem., 1992 Jun;24(6):967-73.
    PMID: 1612186
    1. The L-amino acid oxidase of the monocellate cobra (Naja naja kaouthia) venom was purified to electrophoretic homogeneity. The molecular weight of the enzyme was 112,200 as determined by Sephadex G-200 gel filtration chromatography, and 57,400 as determined by SDS-polyacrylamide gel electrophoresis. 2. The enzyme had an isoelectric point of 8.12 and a pH optimum of 8.5. It showed remarkable thermal stability, and, unlike many venom L-amino acid oxidase, was also stable in alkaline medium. The enzyme was partially inactivated by freezing. 3. The enzyme was very active against L-phenylalanine and L-tyrosine, moderately active against L-tryptophan, L-methionine, L-leucine, L-norleucine, L-arginine and L-norvaline. Other L-amino acids were oxidized slowly or not oxidized. 4. Kinetic studies suggest the presence of a side-chain binding site in the enzyme, and that the binding site comprises of at least four hydrophobic subsites.
    Matched MeSH terms: Chromatography, Ion Exchange
  13. The rubber elongation factor of rubber trees (Hevea brasiliensis) is the major allergen in latex
    Czuppon AB, Chen Z, Rennert S, Engelke T, Meyer HE, Heber M, et al.
    J Allergy Clin Immunol, 1993 Nov;92(5):690-7.
    PMID: 8227860
    BACKGROUND: Allergy to latex-containing articles is becoming more and more important because it can result in unexpected life-threatening anaphylactic reactions in sensitized individuals.

    METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree.

    RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range.

    CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.

    Matched MeSH terms: Chromatography, Ion Exchange
  14. Immobilization of hydrophobic lipase derivatives on to organic polymer beads
    Basri M, Ampon K, Yunus WM, Razak CN, Salleh AB
    J Chem Technol Biotechnol, 1994 Jan;59(1):37-44.
    PMID: 7764496
    A simple and effective method of lipase immobilization is described. Lipase from Candida rugosa was first modified with several hydrophobic modifiers before being adsorbed on to organic polymer beads. The soluble hydrophobic lipase derivatives adsorbed more strongly on to the various polymers as compared with the native lipase. The optimal adsorption temperature of the native and modified lipases on all the polymers was 40 degrees C. The optimal pH of adsorption was between 6 and 7. Lipase immobilized in this manner produced high catalytic recoveries which are affected by the type of modifiers, degree of modification and type of supports used. Monomethoxypolyethylene glycol (1900) activated with p-nitrophenyl chloroformate was found to be the best modifier of the enzyme at 95% modification, for adsorption to the polymers. Increasing the degree of modification of the enzyme increased the activity which was immobilized. Generally, both native and hydrophobic lipase derivatives showed higher specific activities when immobilized on polar polymers compared with non-polar polymers.
    Matched MeSH terms: Ion Exchange Resins
  15. Synthesis and properties of poly(hydroxamic acid) from crosslinked poly(methacrylate)
    Haron MJ, Wan Md ZW, Desa MZ, Kassim A
    Talanta, 1994 May;41(5):805-7.
    PMID: 18966002
    Poly(hydroxamic acid) chelating ion-exchange resin was prepared from crosslinked poly(methacrylate) beads. The starting polymer was prepared by a suspension polymerization of methacrylate and divinyl benzene. Conversion of the ester groups into the hydroxamic acid was carried out by treatment with hydroxylamine in an alkaline solution. Hydroxamic acid capacity of the product was 2.71 mmol/g. The resin exhibited high affinity towards Fe(III) and Pb ions and its capacities for Fe(III), Pb, Cu, Ni and Co ions were pH dependent. The ability of the resin to carry out the separation of Fe(III)CuCo/Ni and PbNi ions is also reported.
    Matched MeSH terms: Ion Exchange Resins
  16. The accumulation and distribution of trace metals in some localized marine species
    Yusof AM, Rahman NA, Wood AK
    Biol Trace Elem Res, 1994;43-45:239-49.
    PMID: 7710833
    Trace elements, such as As, Co, Cr, Hg, Sb, and Zn, were determined by neutron activation analysis (NAA), whereas Cd, Cu, and Pb were determined by graphite furnace atomic absorption spectroscopy (GFAAS) in clam, crab, prawn, swamp cerith, and mussel samples after digestion by microwave heating under controlled conditions before eluting the solutions through a column of a chelating resin, Chelex-100. The standard used in the determination of percentage volatile elements retained by microwave digestion and also in the activation process was Lobster Hepatopancreas TORT-1, whereas known mixed standards were prepared from nitrate salts to determine the efficiency of the separation procedure at a controlled pH. Mercury and lead detected in crabs exceeded the maximum permissible level. Some species also showed a high affinity toward certain elements, and their levels of accumulation in the tissues of these species corresponded with the concentration of these elements in sediments, especially at sites in the vicinity of an industrial zone.
    Matched MeSH terms: Chromatography, Ion Exchange; Ion Exchange Resins
  17. beta-Galactosidase and its significance in ripening mango fruit
    Ali ZM, Armugam S, Lazan H
    Phytochemistry, 1995 Mar;38(5):1109-14.
    PMID: 7766393
    The fruit extracts of ripening cv. Harumanis mango contained a number of glycosidases and glycanases. Among the glycosidases, beta-D-galactosidase (EC 3.2.1.23) appeared to be the most significant. The enzyme activity increased in parallel with increase in tissue softness during ripening. Mango beta-galactosidase was fractionated into three isoforms, viz. beta-galactosidase I, II and III by a combination of chromatographic procedures on DEAE-Sepharose CL-6B, CM-Sepharose and Sephacryl S-200 columns. Apparent Km values for the respective beta-galactosidase isoforms for p-nitrophenyl beta-D-galactoside were 3.7, 3.3 and 2.7 mM, and their Vmax values were 209, 1024 and 62 nkat mg-1 protein. Optimum activity occurred at ca pH 3.2 for beta-galactosidase I and II, and pH 3.6 for beta-galactosidase III. Mango beta-galactosidase and its isoforms have galactanase activity, and the activity of the latter in the crude extracts generally increased during ripening. The close correlation between changes in beta-galactosidase activity, tissue softness, and increased pectin solubility and degradation suggests that beta-galactosidase might play an important role in cell wall pectin modification and softening of mango fruit during ripening.
    Matched MeSH terms: Chromatography, Ion Exchange
  18. Fermentation and recovery of glutamic acid from palm waste hydrolysate by Ion-exchange resin column
    Das K, Anis M, Azemi BM, Ismail N
    Biotechnol Bioeng, 1995 Dec 5;48(5):551-5.
    PMID: 18623521
    Glutamic acid produced from palm waste hydrolysate by fermentation with Brevibacterium lactofermentum ATCC 13869 is produced with a remarkably high yield compared with that produced from pure glucose as a carbon source. The produce yield is 70 g/L with glucose, wherease, when palm waste hydrolysate is the fermentation medium in the same bioreactor under same conditions, it is 88 g/L. The higher yield may be attributed to the fact that this organism has the ability to convert sugars other than only glucose present in the hydrolysate. Bioreactor conditions most conducive for maximum production are pH 7.5, temperature of 30 degrees rmentation period of 48 h, inoculum size 6%, substrate concentration of 10 g per 100 mL, yeast extract 0.5 g per 100 mL as a suitable N source, and biotin at a concentration of 10 pg/L. Palm waste hydrolysate used in this study was prepared by enzymic saccharification of treated palm press fiber under conditions that yielded a maximum of 30 g/L total reducing sugars. Glutamic acid from fermentation broth was recovered by using a chromatographic column (5cm x 60 cm) packed with a strong ion-exchange resin. The filtered broth containing glutamic acid and other inorganic ions was fed to the fully charged column. The broth was continuously recycled at a flow rate of 50 mL/min (retention time of 55 min) until glutamic acid was fully adsorbed on the column leaving other ions in the effluent. Recovery was done by eluting with urea and sodium hydroxide for total displacement of glutamic acid from the resin. The eluent containing 88 g/L of glutamic acid was concentrated by evaporation to obtain solid crystals of the product. (c) 1995 John Wiley & Sons, Inc.
    Matched MeSH terms: Ion Exchange Resins
  19. Penspesiesan Ion-ion Ferum dengan Resin Poli (Asid Hidroksamik)(Speciation of Iron Ions Using Poly(Hydroxamic Acid)) Resin
    Wan Md Zin Wan Yunus, Md Jelas Haron
    Sains Malaysiana, 1996;25.
    Poly(hydroxamic acid) ion exchange resin was evaluated for speciation of iron(II) and iron(III) ions. Distribution coefficients indicate that the resin is more selective towards iron(III) ion. Column extractions show that iron(III) ion is quantatively extracted from sulfuric acid solutions at concentrations of between 0.01 to 0.00lM but only 2% or less of iron(II) ion is retained under these conditions. Further studies show that these two ions can be separated and their separations are not affected by the presence of nickel, zinc, copper, calcium, chloride, bromide, nitrate and sulphate.
    Resin penukar ion poli(asid hidroksamik) telah dikaji untuk penspesiesan ion-ionferum. Pekali taburan menunjukkan resin ini mempunyai kepilihan yang tinggi terhadap ion ferik berbanding dengan ionferus. Pengekstrakan dengan kaedah turus mendapati ion ferik dari larutan asid sulfurik 0.01 dan 0.00lM boleh diesktrak secara kuantitatif manakala pengekstrakan ion ferus hanya 2% atau lebih kecil. Kajian lanjut menunjukkan resin ini boleh memisahkan ion ferik dari ion ferus dan pemisahan ini tidak diganggu oleh kehadiran ion-ion nikel, zink, kuprum, kalsium, klorida, bromida, nitrat dan sulfat.
    Matched MeSH terms: Ion Exchange Resins
  20. 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, Ion Exchange
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