Cloning and expression of a glucoamylase gene from Lactobacillus amylovorus ATCC 33621 in Escherichia coli

James, Jennylynd; Robert, Normand; Lee, Byong H.

doi:10.1007/bf00129344

Cited by 3 publications

(1 citation statement)

References 19 publications

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“…[6][7][8][9][10][11][12]. There is hardly any information available on the secondary or tertiary structures of glucoamylases optimally active around neutral pH, although the primary structures of some of these enzymes have been determined [13,14].…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Neutral and Thermostable Glucoamylase from the Thermophilic Mold Thermomucor indicae-seudaticae: Activity, Stability, and Structural Correlation

Kumar

Islam

Ahmad

et al. 2009

Appl Biochem Biotechnol

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Glucoamylase from the thermophilic mold Thermomucor indicae-seudaticae was purified by anion exchange and gel filtration chromatographic techniques using a fast protein liquid chromatographic system. The structure and thermal stability of this unique 'thermostable and neutral glucoamylase' were analyzed by circular dichroism (CD). T. indicae-seudaticae glucoamylase (TGA) contained typical aromatic amino acid (tryptophan/tyrosine) fingerprints in its tertiary structure. Analysis of the far-UV CD spectrum at pH 7.0 and 25 degrees Celsius revealed the presence of 45% alpha-helix, 43% beta-sheet, and 12% remaining structures. The alpha-helix content was highest at pH 7.0, where glucoamylase is optimally active. This observation points towards the possible (alpha/alpha)(6) barrel catalytic domain in TGA, as reported in microbial glucoamylases. Thermal denaturation curves of the pure protein at different pH values revealed maximum stability at pH 7.0, where no change in the secondary structure was observed upon heating in the temperature range between 20 degrees Celsius and 60 degrees Celsius. The observed midpoint of thermal denaturation (T (m)) of glucoamylase at pH 7.0 was 67.1 degrees Celsius, which decreased on either sides of this pH. Thermostability of TGA enhanced in the presence of starch (0.1%) as no transition curve was obtained in the temperature range between 20 degrees Celsius and 85 degrees Celsius. The only product of TGA action on starch was glucose, and it did not exhibit transglycosylation activity even at 40% glucose that can also be considered as an advantage during starch saccharification.

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Section: Introductionmentioning

confidence: 99%

Characterization of a Neutral and Thermostable Glucoamylase from the Thermophilic Mold Thermomucor indicae-seudaticae: Activity, Stability, and Structural Correlation

Kumar

Islam

Ahmad

et al. 2009

Appl Biochem Biotechnol

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Microbial glucoamylases: characteristics and applications

Kumar

Satyanarayana

2009

Critical Reviews in Biotechnology

164

111

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Glucoamylase is one of the oldest and widely used biocatalysts in food industry. The major application of glucoamylase is the saccharification of partially processed starch/dextrin to glucose, which is an essential substrate for numerous fermentation processes and a range of food and beverage industries. Glucoamylase for commercial purposes has traditionally been produced employing filamentous fungi, although a diverse group of microorganisms is reported to produce glucoamylase, since they secrete large quantities of the enzyme extracellularly. The commercially used fungal glucoamylases have certain limitations such as moderate thermostability, acidic pH requirement, and slow catalytic activity that increase the process cost. Consequently, the search for newer glucoamylases and protein engineering to improve pH and temperature optima leading to amelioration in catalytic efficiency of existing enzymes have been the major areas of research over the years. The present review focuses attention on the recent advances in molecular biology and protein engineering of glucoamylase to improve its production and functional properties including the so far success achieved in isolating mutants with enhanced thermostability and selectivity, higher pH optimum and improved catalytic activity. A comprehensive account is included on the diversity, regulation of production, classification, purification and properties, and potential applications of microbial glucoamylases to provide an overview on all the important aspects of the enzyme.

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Glucoamylases: Microbial Sources, Industrial Applications and Molecular Biology ? A Review

James

Lee

1997

J Food Biochemistry

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Glucoamylase (EC 3.2.1.3) hydrolyzes polysaccharides from the nonreducing chain ends by cleaving α‐1,4 and α‐1,6 glycosidic bonds consecutively. Glucoamylases are used mainly in the production glucose syrup, high fructose corn syrup, and in whole grain and starch hydrolysis for alcohol production. This paper reviews the status of glucoamylases with respect to microbial sources, biochemical and physical properties. Methods used to assay glucoamylase activity are also compared, with reference being made to the specificity of spectrophotometric methods in detecting end products of the enzyme action. Commercial glucoamylases and development of immobilization techniques are discussed. Also, structural analysis of glucoamylase and the main amino acids involved in catalysis and starch binding are emphasized. The cloning of the glucoamylase gene in Saccharomyces cerevisiae for the brewing of low calorie beer is presented. This review highlights the use of glucoamylase in the food industry.

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Cloning and expression of a glucoamylase gene from Lactobacillus amylovorus ATCC 33621 in Escherichia coli

Cited by 3 publications

References 19 publications

Characterization of a Neutral and Thermostable Glucoamylase from the Thermophilic Mold Thermomucor indicae-seudaticae: Activity, Stability, and Structural Correlation

Characterization of a Neutral and Thermostable Glucoamylase from the Thermophilic Mold Thermomucor indicae-seudaticae: Activity, Stability, and Structural Correlation

Microbial glucoamylases: characteristics and applications

Glucoamylases: Microbial Sources, Industrial Applications and Molecular Biology ? A Review

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