Abstract:
:The enzyme levanase encoded by the sacC gene from Bacillus subtilis was overexpressed in Escherichia coli with the strong, inducible tac promoter. The enzyme was purified from crude E. coli cell lysates by salting out with ammonium sulfate and chromatography on DEAE-Sepharose CL-6B, S-Sepharose, and MonoQ-Sepharose. The purified protein had an apparent molecular mass of 75,000 Da in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which is in agreement with that expected from the nucleotide sequence. Levanase was active on levan, inulin, and sucrose with Km values of 1.2 microM, 6.8 mM, and 65 mM, respectively. The pH optimum of the enzyme acting on inulin was 5.5, and the temperature optimum was 55 degrees C. Levanase was rapidly inactivated at 60 degrees C, but activity could be retained for longer times by adding fructose or glycerol. The enzyme activity was completely inactivated by Ag+ and Hg2+ ions, indicating that a sulfhydryl group is involved. A ratio of sucrase to inulinase activity of 1.2 was found for the purified enzyme with substrate concentrations of 50 mg/ml. The mechanism of enzyme action was investigated. No liberation of fructo-oligomers from inulin and levan could be observed by thin-layer chromatography and size exclusion chromatography-low-angle laser light scattering-interferometric differential refractive index techniques. This indicates that levanase is an exoenzyme acting by the single-chain mode.
journal_name
Appl Environ Microbioljournal_title
Applied and environmental microbiologyauthors
Wanker E,Huber A,Schwab Hdoi
10.1128/AEM.61.5.1953-1958.1995subject
Has Abstractpub_date
1995-05-01 00:00:00pages
1953-8issue
5eissn
0099-2240issn
1098-5336journal_volume
61pub_type
杂志文章abstract::Clostridium sp. strain S1, an unnamed bile acid-desulfating strain from rat intestinal microflora (S.M. Huijghebaert, J. A. Mertens, and H. J. Eyssen, Appl. Environ. Microbiol. 43:185-192, 1982), was examined for its ability to desulfate different bile acid sulfates and steroid sulfates in growing cultures. Clostridiu...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.44.5.1030-1034.1982
更新日期:1982-11-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00088-11
更新日期:2011-06-01 00:00:00
abstract::[This corrects the article on p. 1580 in vol. 58.]. ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:
更新日期:1992-08-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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pub_type: 杂志文章
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journal_title:Applied and environmental microbiology
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:1985-10-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.56.6.1672-1677.1990
更新日期:1990-06-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.67.5.2051-2055.2001
更新日期:2001-05-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.38.6.1040-1044.1979
更新日期:1979-12-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.59.3.860-866.1993
更新日期:1993-03-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.61.9.3422-3429.1995
更新日期:1995-09-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.69.10.6189-6200.2003
更新日期:2003-10-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:2014-07-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01521-14
更新日期:2014-10-01 00:00:00
abstract::Salmonella enterica contamination in foods is a significant concern for public health. When DNA detection methods are used for analysis of foods, one of the major concerns is false-positive results from the detection of dead cells. To circumvent this crucial issue, a TaqMan quantitative real-time RT-PCR (qRT-PCR) assa...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.02686-08
更新日期:2009-06-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.72.1.472-477.2006
更新日期:2006-01-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.51.1.115-122.1986
更新日期:1986-01-01 00:00:00
abstract::Vibrio parahaemolyticus and Vibrio vulnificus are naturally occurring estuarine bacteria and are the leading causes of seafood-associated infections and mortality in the United States. Though multiple-antibiotic-resistant V. parahaemolyticus and V. vulnificus strains have been reported, resistance patterns in vibrios ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:2018-01-17 00:00:00
abstract:UNLABELLED:Lactobacillus rhamnosus GG is a lactic acid bacterium widely marketed by the food industry. Its genomic analysis led to the identification of a gene cluster encoding mucus-binding SpaCBA pili, which is located in a genomic island enriched in insertion sequence (IS) elements. In the present study, we analyzed...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:2016-06-13 00:00:00
abstract::This study used the technique of waiting time modeling to analyze the combined effects of temperature, pH, carbohydrate, protein, and lipid on the time-to-toxicity of Clostridium botulinum 56A. Waiting time models can be used whenever the time to the occurrence of some event is the variable of interest. In the case of...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.64.11.4416-4422.1998
更新日期:1998-11-01 00:00:00
abstract::The importance of hydrogenase activity to corrosion of steel was assessed by using mixed populations of sulfate-reducing bacteria isolated from corroded and noncorroded oil pipelines. Biofilms which developed on the steel studs contained detectable numbers of sulfate-reducing bacteria (10 increasing to 10/0.5 cm). How...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.57.10.2804-2809.1991
更新日期:1991-10-01 00:00:00
abstract::Oil field bacteria were characterized by cloning and sequencing of PCR-amplified 16S rRNA genes. A variety of gram-negative, sulfate-reducing bacteria was detected (16 members of the family Desulfovibrionaceae and 8 members of the family Desulfobacteriaceae). In contrast, a much more limited number of anaerobic, ferme...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.62.5.1623-1629.1996
更新日期:1996-05-01 00:00:00
abstract::Strain selection and improvement in the baker's yeast industry have aimed to increase the speed of maltose fermentation in order to increase the leavening activity of industrial baking yeast. We identified two groups of baker's strains of Saccharomyces cerevisiae that can be distinguished by the mode of regulation of ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.65.2.680-685.1999
更新日期:1999-02-01 00:00:00
abstract::Vibrio alginolyticus is one of the most abundant microorganisms in marine environments and is also an opportunistic pathogen mediating high-mortality vibriosis in marine animals. Alternative sigma factors play essential roles in bacterial pathogens in the adaptation to environmental changes during infection and the ad...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:2019-07-01 00:00:00
abstract::The presence or absence of molecular oxygen has been shown to play a crucial role in the degradability of haloaromatic compounds. In the present study, it was shown that anaerobic phototrophic 3-chlorobenzoate (3CBA) metabolism by Rhodopseudomonas palustris DCP3 is oxygen tolerant up to a concentration of 3 microM O2....
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.65.1.131-137.1999
更新日期:1999-01-01 00:00:00