Linked Life Data

9758774

Source:http://linkedlifedata.com/resource/pubmed/id/9758774

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1998-11-24
pubmed:abstractText
Aspergillus oryzae was found to secrete two distinct beta-glucosidases when it was grown in liquid culture on various substrates. The major form had a molecular mass of 130 kDa and was highly inhibited by glucose. The minor form, which was induced most effectively on quercetin (3,3',4',5,7-pentahydroxyflavone)-rich medium, represented no more than 18% of total beta-glucosidase activity but exhibited a high tolerance to glucose inhibition. This highly glucose-tolerant beta-glucosidase (designated HGT-BG) was purified to homogeneity by ammonium sulfate precipitation, gel filtration, and anion-exchange chromatography. HGT-BG is a monomeric protein with an apparent molecular mass of 43 kDa and a pI of 4.2 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing polyacrylamide gel electrophoresis, respectively. Using p-nitrophenyl-beta-D-glucoside as the substrate, we found that the enzyme was optimally active at 50 degreesC and pH 5.0 and had a specific activity of 1,066 micromol min-1 mg of protein-1 and a Km of 0.55 mM under these conditions. The enzyme is particularly resistant to inhibition by glucose (Ki, 1. 36 M) or glucono-delta-lactone (Ki, 12.5 mM), another powerful beta-glucosidase inhibitor present in wine. A comparison of the enzyme activities on various glycosidic substrates indicated that HGT-BG is a broad-specificity type of fungal beta-glucosidase. It exhibits exoglucanase activity and hydrolyzes (1-->3)- and (1-->6)-beta-glucosidic linkages most effectively. This enzyme was able to release flavor compounds, such as geraniol, nerol, and linalol, from the corresponding monoterpenyl-beta-D-glucosides in a grape must (pH 2.9, 90 g of glucose liter-1). Other flavor precursors (benzyl- and 2-phenylethyl-beta-D-glucosides) and prunin (4',5,7-trihydroxyflavanone-7-glucoside), which contribute to the bitterness of citrus juices, are also substrates of the enzyme. Thus, this novel beta-glucosidase is of great potential interest in wine and fruit juice processing because it releases aromatic compounds from flavorless glucosidic precursors.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-2532041, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-33973, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-5432063, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-7492960, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-7763458, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-7925351, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-8002477, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-8156553, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-8795205, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-9017925, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-9150209, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-9214755, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-9291624, http://linkedlifedata.com/resource/pubmed/commentcorrection/9758774-942051
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0099-2240
pubmed:author
pubmed:issnType
Print
pubmed:volume
64
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3607-14
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Purification, characterization, and substrate specificity of a novel highly glucose-tolerant beta-glucosidase from Aspergillus oryzae.
pubmed:affiliation
Laboratoire de Microbiologie et Technologie des Fermentations, Institut National de la Recherche Agronomique, Institut des Produits de la Vigne, F-34060 Montpellier Cedex 2, France. riou@ensam.inra.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't