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dc.contributor.authorVettori, Mary Helen P. B. [UNESP]
dc.contributor.authorMukerjea, Rupendra
dc.contributor.authorRobyt, John F.
dc.identifier.citationCarbohydrate Research. Oxford: Elsevier B.V., v. 346, n. 9, p. 1077-1082, 2011.
dc.description.abstractA comparative study of nine assay methods for dextransucrase and related enzymes has been made. A relatively widespread method for the reaction of dextransucrase with sucrose is the measurement of the reducing value of D-fructose by alkaline 3,5-dinitrosalicylate (DNS) and thereby the amount of D-glucose incorporated into dextran. Another method is the reaction with C-14-sucrose with the addition of an aliquot to Whatman 3MM paper squares that are washed three times with methanol to remove C-14-D-fructose and unreacted C-14-sucrose, followed by counting of C-14-dextran on the paper by liquid scintillation counting (LSC). It is shown that both methods give erroneous results. The DNS reducing value method gives extremely high values due to over-oxidation of both D-fructose and dextran, and the C-14-paper square method gives significantly low values due to the removal of some of the C-14-dextran from the paper by methanol washes. In the present study, we have examined nine methods and find two that give values that are identical and are an accurate measurement of the dextransucrase reaction. They are (1) a C-14-sucrose/dextransucrase digest in which dextran is precipitated three times with three volumes of ethanol, dissolved in water, and added to paper and counted in a toluene cocktail by LSC: and (2) precipitation of dextran three times with three volumes of ethanol from a sucrose/dextransucrase digest, dried, and weighed. Four reducing value methods were examined to measure the amount of D-fructose. Three of the four (two DNS methods, one with both dextran and D-fructose and the other with only D-fructose, and the ferricyanide/arsenomolybdate method with is-fructose) gave extremely high values due to over-oxidation of D-fructose, D-glucose, leucrose, and dextran. (C) 2011 Elsevier Ltd. All rights reserved.en
dc.publisherElsevier B.V.
dc.relation.ispartofCarbohydrate Research
dc.sourceWeb of Science
dc.subjectDextransucrase assaysen
dc.subjectDirect measurement of dextransen
dc.subjectReducing valuesen
dc.titleComparative study of the efficacies of nine assay methods for the dextransucrase synthesis of dextranen
dcterms.rightsHolderElsevier B.V.
dc.contributor.institutionIowa State Univ
dc.contributor.institutionUniversidade Estadual Paulista (UNESP)
dc.description.affiliationIowa State Univ, Dept Biochem Biophys & Mol Biol, Lab Carbohydrate Chem & Enzymol, Ames, IA 50011 USA
dc.description.affiliationUnesp Univ Estadual Paulista, Inst Biol Sci, Dept Biochem & Microbiol, São Paulo, Brazil
dc.description.affiliationUnespUnesp Univ Estadual Paulista, Inst Biol Sci, Dept Biochem & Microbiol, São Paulo, Brazil
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