• Title/Summary/Keyword: branched-cyclodextrin

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Characterization and Some Cultural Conditions of a Pullulanase Producing Aeromonas caviae No. S-76 (Pullulanase를 생산하는 Aeromonas caviae No.S-76의 특성과 배양조건)

  • 손천배;김명희;이명자
    • Microbiology and Biotechnology Letters
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    • v.19 no.4
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    • pp.315-318
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    • 1991
  • - A bacterial strain No. S-76 which produced pullulanase powerfully was isolated frorn soil. The isolated bacterium was 0.4~$0.6\times 0.8$~1.4 $\mu\textrm{m}$ in size, gram negative, rods, motile and was identified as Aerornonas caviae by Bergey's manual of determinative bacteriology with various characteristics investigated. The highest yield of pullulanase of the strain was obtained by using the following medium: 1% pullulan, soluble starch or corn starch as a carbon sources and 0.5% yeast extract, peptone as nitrogen sources with an initial pH of 9.0. The optimal cutture conditions for production of pullulanase were at $32^{\circ}C$ for 2 days.

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Purification, Characterization of Pullulanase Produced by Aerornonas caviae No. S-76 and Synthesis of Maltosyl-$\beta$-Cyclodextrin (Aeromonas caviae No. S-76이 생산하는 Pullulanase의 정제, 특성 및 Maltosyl-$\beta$-Cyclodextrin의 합성)

  • 손천배;김명희;이명자
    • Microbiology and Biotechnology Letters
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    • v.19 no.4
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    • pp.362-367
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    • 1991
  • The crude enzyme solution obtained by shaking culture of Aeromonas caviae No. S-76 isolated from soil as pullulanase producing bacterium was purified by 50 folds with 21% yield by salting out with ammonium sulfate and column chromatography using DEAE-Sephadex A-50 and Sephadex G-150. The purified pullulanase had a molecular weight of 118, 000 approximately by SDS-polyacrylamide slab gel electrophoresis and pI of 4.3 by isoelectric focusing. And optimum reaction temperature and pH for puHulanase were $50^{\circ}C$ and 8.0, respectively. The purified enzyme was relatively stable at pH 6.0~9.0 and below $45^{\circ}C$. This enzyme synthesized maltosyl-$\beta$-cyclodextrin from mixture of $\beta$-cyclodextrin and maltose.

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Characterization of the Transglycosylation Reaction of 4-α-Glucanotransferase (MalQ) and Its Role in Glycogen Breakdown in Escherichia coli

  • Nguyen, Dang Hai Dang;Park, Sung-Hoon;Tran, Phuong Lan;Kim, Jung-Wan;Le, Quang Tri;Boos, Winfried;Park, Jong-Tae
    • Journal of Microbiology and Biotechnology
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    • v.29 no.3
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    • pp.357-366
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    • 2019
  • We first confirmed the involvement of MalQ (4-${\alpha}$-glucanotransferase) in Escherichia coli glycogen breakdown by both in vitro and in vivo assays. In vivo tests of the knock-out mutant, ${\Delta}malQ$, showed that glycogen slowly decreased after the stationary phase compared to the wild-type strain, indicating the involvement of MalQ in glycogen degradation. In vitro assays incubated glycogen-mimic substrate, branched cyclodextrin (maltotetraosyl-${\beta}$-CD: G4-${\beta}$-CD) and glycogen phosphorylase (GlgP)-limit dextrin with a set of variable combinations of E. coli enzymes, including GlgX (debranching enzyme), MalP (maltodextrin phosphorylase), GlgP and MalQ. In the absence of GlgP, the reaction of MalP, GlgX and MalQ on substrates produced glucose-1-P (glc-1-P) 3-fold faster than without MalQ. The results revealed that MalQ led to disproportionate G4 released from GlgP-limit dextrin to another acceptor, G4, which is phosphorylated by MalP. In contrast, in the absence of MalP, the reaction of GlgX, GlgP and MalQ resulted in a 1.6-fold increased production of glc-1-P than without MalQ. The result indicated that the G4-branch chains of GlgP-limit dextrin are released by GlgX hydrolysis, and then MalQ transfers the resultant G4 either to another branch chain or another G4 that can immediately be phosphorylated into glc-1-P by GlgP. Thus, we propose a model of two possible MalQ-involved pathways in glycogen degradation. The operon structure of MalP-defecting enterobacteria strongly supports the involvement of MalQ and GlgP as alternative pathways in glycogen degradation.