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|Title: ||Characterization of the thermophilic isoamylase from the thermophilic archaeon Sulfolobus solfataricus ATCC 35092|
|Authors: ||Tsuei-Yun Fang;Wen-Chi Tseng;Ching-Ju Yu;Tong-Yuan Shih|
|Contributors: ||NTOU:Department of Food Science|
|Keywords: ||Thermophilic;Isoamylase;Trehalose;Starch;Sulfolobus solfataricus;E. coli|
|Issue Date: ||2011-10-21T02:23:46Z
|Publisher: ||Journal of Molecular Catalysis B: Enzymatic|
|Abstract: ||Abstract:Isoamylase catalyzes the hydrolysis of α-1,6-glucosidic linkages of starch and related polysaccharides. In this study, the treX gene (GenBank accession no. AE006815 REGION: 9279 … 11435) encoding the thermophilic isoamylase was PCR-cloned from the genomic DNA of Sulfolobus solfataricus ATCC 35092 to an expression vector with a T7lac promoter. Both wild-type and His-tagged isoamylases were expressed in Escherichia coli. The wild-type isoamylase was purified sequentially using heat treatment, nucleic acid precipitation, ion-exchange chromatography, and gel filtration chromatography while the His-tagged isoamylase was purified from the cell-free extract directly by metal chelating chromatography. Both enzymes were active only under their homo-trimer forms. In the absence of NaCl, both enzymes became inactive monomers. In addition, both enzymes were more stable when being stored at room temperature than at 4 °C. They had an apparent optimal pH of 5 and an optimal temperature at 75 °C. The enzyme activities remained unchanged after a 2 h incubation at 80 and 75 °C for the wild-type and His-tagged enzymes, respectively. These thermophilic isoamylases showed a potential to be used in industry to degrade the branching points of starch at a high temperature.|
|Relation: ||33(3-6), pp.99–107|
|Appears in Collections:||[食品科學系] 期刊論文|
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