Isoamylase and its Industrial Significance in the Production of Sugars from Starch

Harada, Tokuya

doi:10.1080/02648725.1984.10647780

Cited by 22 publications

(6 citation statements)

References 78 publications

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“…The native enzyme exists as a monomer with molecular weight of 86 000, and is distinguished from other isoamylases by its acidic pH optimum (3±4). This enzyme has been useful in elucidation of ®ne structures of a-glucan polysaccharides, and, in conjunction with bamylase, for large-scale industrial production of maltose from starch (Harada 1984). To date, the only bacterial isoamylase (iam) genes that have been cloned and sequenced are from P. amyloderamosa SB15 (Amemura et al 1988), Pseudomonas sp.…”

Section: Introductionmentioning

confidence: 99%

“…Isoamylase is considered a direct debranching enzyme and is dierentiated from the other major starch-debranching enzyme, pullulanase, by its ability to cleave all the a-1,6 linkages of glycogen but not those of pullulan, whereas pullulanase completely hyrolyzes pullulan to maltotriose but has limited debranching activity on glycogen (Harada 1984;Lee and Whelan 1971). Bacteria known to produce isoamylase include Pseudomonas sp.…”

Section: Introductionmentioning

confidence: 99%

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An isoamylase with neutral pH optimum from a Flavobacterium species: cloning, characterization and expression of the iam gene

1997

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The gene encoding an isoamylase with neutral pH optimum (iam) from a Flavobacterium species was cloned using a PCR probe generated from highly conserved regions of amylolytic enzymes. Active isoamylase was expressed from a 4.9-kb Pst I fragment in Escherichia coli, and was detected in the extracellular medium by a plate assay. The iam nucleotide sequence has an open reading frame of 2334 nucleotides (778 amino acids) with a GC content of 69%. Sequence analysis suggests that transcriptional control of the Flavobacterium sp. iam gene is mediated through the product of a malT regulatory gene. The deduced amino acid sequence of iam contained an N-terminal signal peptide of 32 amino acids, and was 61% homologous with Pseudomonas amyloderamosa isoamylase. The mature enzyme, which was engineered for overexpression in E. coli and purified to homogeneity, has a relative molecular mass of 83 kDa, a pH optimum of 6-7, and a highest rate of hydrolysis for glycogen (but did not cleave pullulan). Polyclonal antiserum generated from purified donor isoamylase cross-reacted with crude and purified recombinant isoamylase from E. coli. This is the first report of the cloning, characterization, and sequence of an novel isoamylase that has a neutral pH optimum. A comparison of the sequence of Flavobacterium sp. iam with acidic isoamylase from Pseudomonas sp. identified putative residues which may be associated with the pH for optimal activity of isoamylases.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An isoamylase with neutral pH optimum from a Flavobacterium species: cloning, characterization and expression of the iam gene

1997

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“…In converting starch into high maltose syrups which generally contain 70±80% maltose (dry base), the debranching enzymes must be incorporated within the sacchari®cation processes [9]. Isoamylase (EC 3.2.1.68, glycogen 6-glucanohydrolase), i.e.…”

Section: Introductionmentioning

confidence: 99%

“…a major extracellular enzyme involved in the hydrolysis process, can cleave the branching points (a-1,6-glucosidic linkages) in amylopectin, removing the side branches of various lengths from the main polymer chain. This enzyme plays a prominent role in producing high-maltose, glucose syrups, and amyloses from starch [1,9,19,27] with other amylases such as aamylase, b-amylase and glucoamylase. However, the debranching enzyme's high cost makes reuse desirable in most applications [1,32].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the immobilization of Pseudomonas isoamylase onto polysaccharide matrices

Lai

Liu

1998

Bioprocess Engineering

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This study examined Pseudomonas isoamylase immobilized onto polysaccharide matrices, among which included agarose, cellulose, and raw corn starch. For chemical binding of polysaccharides activated with tosyl chloride, a high speci®c activity of 23144 U/g-starch was obtained as compared with matrices of cellulose and agarose with 3229 U/g-cellulose and 84 U/g-agarose, respectively.For raw corn starch, isoamylase desorption occurred when the immobilized enzyme by physical adsorption was subjected to 0.05 M acetate buffer with pH 5.2 at 40°C; this is despite the considerable af®nity between the enzyme and the matrix. In contrast, no detectable activity leached from the matrix for chemical binding, regardless of whether maltose, i.e. an af®nity species to isoamylase, was added. For immobilized starch-isoamylase, its optimal activity performance was obtained in broader pH ranges of 3.5±5.5 and 5°C higher than those of the free enzymes. More speci®cally, the free enzyme's activity markedly decreased within ®ve hours while the immobilized starchisoamylase exhibited a fairly stable behavior over a three day incubation period at 40°C. After 175 days of storage at 4°C, the residues of relative activity of 75% and 45% were obtained with respect to immobilized and free isoamylases, respectively.

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“…Asnl82-»Asp mutations (Table 4) be identified in addition to higher polymers (Norman, 1979;Harada, 1984;Linko, 1987, Nikolov et ai., 1989.…”

Section: Cgt 220-g M G V D G I R F Dmentioning

confidence: 99%

Tailoring the pH dependence of glucoamylase from Aspergillus awamori by mutagenesis

Bakır

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Properties of glucoamylase 3 Explanation of the dissertation format 13 PART I. TAILORING THE pH DEPENDENCE OF Aspergillus awamori GLUCOAMYLASE BY MUTAGENESIS 15 Research objectives 29 MATERIALS AND METHODS Genetic engineering of glucoamylase Production and purification of mutant glucoamylases Kinetic experiments RESULTS DISCUSSION CONCLUSIONS AND RECOMMENDATIONS PART II. FERMENTATIVE PRODUCTION AND HYDROLYSIS KINETICS OF Aspergillus awamori GLUCOAMYLASE INTRODUCTION 113 RESEARCH OBJECTIVES

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Isoamylase and its Industrial Significance in the Production of Sugars from Starch

Cited by 22 publications

References 78 publications

An isoamylase with neutral pH optimum from a Flavobacterium species: cloning, characterization and expression of the iam gene

An isoamylase with neutral pH optimum from a Flavobacterium species: cloning, characterization and expression of the iam gene

Investigation on the immobilization of Pseudomonas isoamylase onto polysaccharide matrices

Tailoring the pH dependence of glucoamylase from Aspergillus awamori by mutagenesis

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