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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1993-5-21
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pubmed:abstractText |
Cell-free extracts of cellobiose-grown cells of the hyperthermophile Pyrococcus furiosus contain very high activities (19.8 U/mg) of a beta-glucosidase. The cytoplasmic enzyme was purified 22-fold to apparent homogeneity, indicating that the enzyme comprises nearly 5% of the total cell protein. The native beta-glucosidase has a molecular mass of 230 +/- 20 kDa, composed of 58 +/- 2-kDa subunits. The enzyme has a pI of 4.40. Thiol groups are not essential for activity, nor is the enzyme dependent on divalent cations or a high ionic strength. The enzyme shows optimum activity at pH 5.0 and 102-105 degrees C. From Lineweaver-Burk plots, Vmax values of 470 U/mg and 700 U/mg were found for cellobiose (Km = 20 mM) and p-nitrophenyl-beta-D-glucopyranoside (Km = 0.15 mM), respectively. The purified enzyme also exhibits high beta-galactosidase activity and beta-xylosidase activity, but shows no activity towards alpha-linked disaccharides or beta-linked polymers, like cellulose. The purified beta-glucosidase shows a remarkable thermostability with a half life of 85 h at 100 degrees C and 13 h at 110 degrees C.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0014-2956
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
213
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
305-12
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:8477701-Archaea,
pubmed-meshheading:8477701-Carbohydrate Sequence,
pubmed-meshheading:8477701-Catalysis,
pubmed-meshheading:8477701-Cell-Free System,
pubmed-meshheading:8477701-Cellobiose,
pubmed-meshheading:8477701-Chromatography, Gel,
pubmed-meshheading:8477701-Electrophoresis, Polyacrylamide Gel,
pubmed-meshheading:8477701-Enzyme Stability,
pubmed-meshheading:8477701-Hot Temperature,
pubmed-meshheading:8477701-Kinetics,
pubmed-meshheading:8477701-Molecular Sequence Data,
pubmed-meshheading:8477701-Substrate Specificity,
pubmed-meshheading:8477701-beta-Glucosidase
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pubmed:year |
1993
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pubmed:articleTitle |
Purification and characterization of an extremely thermostable beta-glucosidase from the hyperthermophilic archaeon Pyrococcus furiosus.
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pubmed:affiliation |
Department of Microbiology, Wageningen Agricultural University, The Netherlands.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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