• Title, Summary, Keyword: acceptor reaction

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Biosynthesis of New Oligosaccharides via Acceptor Reaction using Fructosyloligosaccharide as an Acceptor (Fructosyloligosaccharide를 Acceptor 반응의 기질로 사용한 새로운 올리고당의 생합성)

  • 이찬용;이충환
    • Korean Journal of Microbiology
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    • v.35 no.2
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    • pp.146-152
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    • 1999
  • Acceplor reaction of glucosyltr~ansferase of Streptococcus ,SO~~-~IZLIS with f ~ ~ t o ~ y l o l i g o ~ a ~ ~ h a r i d e ~ was studied for the biosynthesis of novel olgisaccharides. First, bacilracin resistant mutants were selected by mutagenesis of Streptococcus sobrimis ATCC27351. Among these mutants 4 strains were selected by resistance to bacitracin and increase of glucosyltransferase. Acceptor reaction of maltose was analyzed by TLC and image analysis. There were differences in the specificity of the acceptor reaclion by Ule glucosylumsferase between mother strain (Streptococcus sobrinus ATCC2735) and bacitracin resistant mutants (Streptococcus sobrinus BR24C, Strepfococcus sobrinus CH-5). Molher strain did ilot show an acceptor reaction with fructosyloligosaccharides such as 1-keqtose and nystose. Acceptor reaction products of turailose and 1-kestose with glucosyltransferase (GW-S) of Streptococcus sobrini~s BR24C were TEX>\6^{3}$-$\alpha$-D-glucopyranosyl \3^{2}$-O-$\alpha$-D-fructose (glucose-fructose-glucose) and \6^{4}$-$\alpha$-D-glucopyranosyl \1^{3}$-$\beta$-D-~-h~ctofuranos~~ sucrose (glucose-glucosefructose- fructose). respectively These are novel oligosaccharides which can be produced only by enzymatic reaction.

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Enzymatic Synthesis of New Oligosaccharides Using Glucansucrases. (Glucansucrases를 이용한 새로운 올리고당의 합성)

  • ;;;;;John F. Robyt
    • Microbiology and Biotechnology Letters
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    • v.26 no.2
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    • pp.179-186
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    • 1998
  • Dextransucrase hyper-producing Leuconostoc mesenteroides B-512FMCM and dextransucrase constitutive mutants B-742CB and B-1355C catalyzed the transfer of glucose from sucrose to other carbohydrates which were present or were added to the reaction digests. When the acceptor was a maltose, gentiobiose, lactose or raffinose, there was produced a series of oligosaccharide acceptor products or single product based on the kinds of enzymes and reaction conditions. To obtain the quantitative information about the yield and the distribution of acceptor products and dextran two experimental parameters were studied: a) the ratio of acceptor to sucrose and b) the amount of enzyme at constant carbohydrate concentration (100 mM). As the amount of enzyme increased, the synthesis of acceptor products (of maltose or gentiobiose) increased, and the formation of dextran decreased. As the ratio of acceptor to sucrose increased, the amount of dextran and the number of acceptor-products decreased and the amount of acceptor-products increased. When maltose or gentiobiose was an acceptor, the glucose from sucrose was transferred to the C-6 hydroxyl group of the nonreducing-end glucose residue of accepters to give a homologous series of isomaltosyl dextrins. In case of lactose or raffinose, there was produced only one acceptor product from B-512FMCM dextransucrase reaction. In the lactose acceptor reaction, the glucose from sucrose was transferred to the C-2 hydroxyl of the reducing end glucose residue of lactose. To get a series of oligosaccharides from lactose or raffinose acceptor reaction we used B-742CB dextransucrase or B-1355C alternansucrase with 500 mM sucrose in reaction digest.

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Acarbose Effect for Dexran Synthesis, Acceptor and Disproportionation Reactions of Leuconostoc mesenteroides B-512FMCM Dextransucrase

  • Kim, Do-Man;Park, Kwan-Hwa;Robyt, John F.
    • Journal of Microbiology and Biotechnology
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    • v.8 no.3
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    • pp.287-290
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    • 1998
  • Acarbose effectively inhibited the synthesis of dextran, and the inhibition pattern was a noncompetitive type with a $K_i$ value of 1.35 mM. It also inhibited the disproportionation reaction of dextransucrase with isomaltotriose and decreased the efficiency of the maltose acceptor reaction. Increased concentration of dextransucrase or maltose in reaction digests, however, decreased the degree of inhibition by acarbose.

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Transglycosylation Reaction on Cellobiose by Dextansucrase of Leuconostoc mesenteroides B512FMC/6HG8 (Leuconostoc mesenteroides B512FMC/6HG8가 생산하는 Dextransucrase에 의한 Cellobiose의 당전이반응)

  • 강현록;양지영;이현규
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.5
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    • pp.802-806
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    • 2000
  • The transglycosylation reaction by dextansucrase from Leuconostoc mesenteroides B512FMC/6HG8 was investigate with cellobiose as an acceptor molecule and sucrose as a donor. he optimal conditions of transglycosylation on cellobiose were found that the ration of sucrose to cellobiose was 3:1, the amount of enzyme was 2U/mL, the ionic strength of buffer was 25 mM, pH was 5.0 and reaction temperature was $25^{\circ}C$. also, acceptor products of cellobiose by transglycosylation were a series of oligosaccharides showing the degree of plymenzation of 6.

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Structural Characteristics of Novel Branched Oligosaccharides Syntesized by a Maltose Acceptor Reaction with Dextransucrase from Leuconostoc mesenteroides M-12 (Leuconostoc mesenteroides M-12 덱스트란수크라제의 말토스 억셉터 반응으로 합성된 새로운 분지 올리고당의 구조 특성)

  • 서현창
    • The Korean Journal of Food And Nutrition
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    • v.10 no.1
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    • pp.102-109
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    • 1997
  • The structures of novel branched oligosaccharides synthesized by the acceptor reaction with dextransucrase from Leuconostoc mesenteriodes M-12 were proposed in accordance with the results obtained from enzymatic hydrolyses and a partial acid hydrolysis. The structure of branched oligosaccharide B4 was shown to be 62-O-$\alpha$-D-kojibiosylmaltose. Branched oligosaccharide B5 was shown to be 63-O-$\alpha$-D-kojibiosylpanose. By reacting the acceptor reaction products with endodextranase a novel branched oligosaccharide (D4) could be produced. D4 was derived from the result of endodextranase hydrolysis of oligosaccarides synthesized by the second acceptor reaction with dextransucrase and was resistant to endodextranase and glucoamylase. The proposed structure of D4 was 62-O-$\alpha$-D-kojibiosylisomaltose. Formation pattern of the acceptor reaction products smaller than d.p. 6 with linear or branched linkage was also shown.

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Sythesis of Highly Branched Isomaltodextrin by Acceptor Reaction using Dextransucrases from L. mesenteroides B-742CB and B-512FMCM (Leuconostoc mesenteroides B-742CB와 B-512FMCM Dextransucrase의 수용체 반응을 이용한 고분지 Isomaltodextrin의 생산)

  • 김문수;이선옥;류화자;강희경;유선균;장석상;김도원;김도만;김성혁
    • KSBB Journal
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    • v.16 no.2
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    • pp.200-206
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    • 2001
  • In this study we tried to optimize the enzyme reaction conditions for the synthesis of highly branched isomaltodextrin (Mw > 2.5 kDa) using two dextransucrases from L. mesenteroides B-742CB and B-512FMCM that are dextransucrase constitutive mutants. As the concentration of sucrose or the ratio of maltose to sucrose increased, the amount of dextran decreased and the number and the amount of acceptor-products (of sucrose or maltose) increased. With high sucrose concentration (over 34%), there was more branched isomaltodextrin (as acceptor products) than dextran. When the ratio of sucrose to maltose was 2.5, there produced 86.7% of isomaltodextrin were produced. The Mw of dextrans, however, was over 2${\times}$10(sup)6 and there was no significant amounts of branched clinical dextran or high molecular weight oligosaccharides. With the combined activities of B-742CB dextransucrase and B-512FMCM dextransucrase we could synthesize high molecular weight branched isomaltodextrin (Mw>2.5 kDa). The high molecular weight dextran was composed of high branches as B-742CB dextran.

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Study of Solvent Effects in Diels-Alder Reaction through Charge Transfer Formation by Using Semi-empirical Calculations

  • Shihab, Mehdi Salih
    • Bulletin of the Korean Chemical Society
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    • v.29 no.10
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    • pp.1898-1904
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    • 2008
  • Study of computational model of the concerted Diels-Alder reaction between 9,10-dimethyl anthracene (as donor) and tetracyanoethylene (as acceptor) in absence and in presence of aromatic solvents (benzene, mesitylene and hexamethylbenzene, as donors) using an AM1 semi-empirical method. AM1 method used to study the neutral charge transfer complex models that could be expected between donor and acceptor during the course of the concerted Diels-Alder reaction. Calculated enthalpies of reaction of the charge transfer complexes models showed physical and chemical meaning for explain the effect of aromatic solvents on the kinetic process of concerted Diels-Alder reaction that contains tetracyanoethylene.

Acceptor reaction of a novel transfructosylating enzyme from Bacillus sp.

  • Kim, Yeong-Mi;Sinha, Jayanta;Park, Jong-Pil;Yun, Jong-Won
    • 한국생물공학회:학술대회논문집
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    • pp.583-586
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    • 2000
  • Many different oligosaccharides were produced by transferring the fructose residue of sucrose to maltose, cellobiose, lactose and sucrose (self-transfer), where their yields of fructosylated acceptor products accounted for $26{\sim}30%$ (w/w). The maximum conversion yield (30%) was obtained in fructosyl cellobioside formation with 500 g sucrose/l (substrate) and 200 g cellobiose/l (acceptor). These four acceptors gave various products having DP (degree of polymerization) $2{\sim}7$ by successive transfer reactions.

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Kinetics and Mechanism for Alkaline Hydrolysis of C. I. Disperse Blue 79 (C. I. Disperse Blue 79의 알칼리 가수분해 반응속도 및 반응메카니즘)

  • 박건용;박창혁;박병기
    • Textile Coloration and Finishing
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    • v.13 no.5
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    • pp.312-319
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    • 2001
  • Kinetics and mechanism for alkaline hydrolysis of C. I. Disperse Blue 79(B-79) which is 4-N, N- diacetoxyethyl -2- acylamino-5-ethos y -2'-bromo-4',6'-dinitroazobenzene were investigated. The color strength of B-79 in acetone/water solutions of various NaOH concentrations decreased continuously. The hydrolysis rate of B-79 increased with increasing alkali concentration and appeared following first order reaction. The observed rate constants for various concentrations of B-79 showed similar values, and B-79 was hydrolyzed by first order reaction for dye concentration. Therefore, it was confirmed that the overall reaction follow second order kinetics and proceed via $S_N2$ reaction. From the study on kinetics and spectrometric analysis, it was proposed that the rate determining step of the hydrolysis reaction of B-79 is the nucleophilic substitution reaction - that is the reaction of the rapid attack of OH- on the carbon atom, which is in acceptor ring, adjacent to auto group to break the C-N bond. And it was also found that the final hydrolysis products of B-79 include both the acceptor ring in the form of sodium salt and the donor ring possessing 4-N,N-dihydroxyethyl group converted from 4-N, N-diacetoxyethyl group.

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Identification of Amino-Acids Residues for Key Role in Dextransucrase Activity of Leuconostoc mesenteroides B-742CB

  • Ryu, Hwa-Ja;Kim, Do-Man;Seo, Eun-Seong;Kang, Hee-Kyung;Lee, Jin-Ha;Yoon, Seung-Heon;Cho, Jae-Young;Robyt, John-F.;Kim, Do-Won;Chang, Suk-Sang;Kim, Seung-Heuk;Kimura, Atsuo
    • Journal of Microbiology and Biotechnology
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    • v.14 no.5
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    • pp.1075-1080
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    • 2004
  • Dextransucrase (DSRB742) from Leuconostoc mesenteroides NRRL B-742CB is a glucosyltransferase that catalyzes the synthesis of dextran using sucrose, or the synthesis of oligosaccharides when acceptor molecules, like maltose, are present. The DSRB742 gene (dsrB742) was cloned and the properties were characterized. In order to identify critical amino acid residues, the DSRB742 amino acid sequence was aligned with glucosyltransferase sequences, and three amino acid residues reported as sucrose binding amino acids in Streptococcus glucosyltransferases were selected for site-directed mutagenesis experiments. Asp-533, Asp-536, and His-643 were independently replaced with Ala or Asn. D533A and D536A dextransucrases showed reduced dextran synthesis activities, 2.3% and 40.8% of DSRB742 dextransucrase, respectively, and D533N, D536N, H643A, end H643N dextransucrases showed complete suppression of dextran synthesis activities altogether. Additionally, D536N dextransucrase showed complete suppression of oligosaccharide synthesis activities. However, modifications at Asp-533 or at His-643 retained acceptor reaction activities in the range of 8.4% to 21.3% of DSRB742 acceptor reaction activity. Thus at least two carboxyl groups of Asp-533 and Asp-536, and His-643 as a proton donor, are essential for the catalysis process.