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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1976-9-2
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pubmed:abstractText |
The kinetic parameters for the maltose transport system in Escherichia coli K12 were determined with maltose and maltotriose as substrates. The system exhibits an apparent Km of 1 muM for maltose and 2 muM for maltotriose. The V of entry was determined as 2.0 and 1.1 nmol substrate/min per 10(8) cells. Mutations in lamB, the structural gene for the receptor protein of phage lambda, increased the Km for maltose transport by a factor of 100-500 without influencing the maximal rate of transport. Maltotriose is no longer transported in these lamB mutants. The maltose-binding protein, an essential component of the maltose transport system, was found to exhibit substrate-dependent fluorescence quenching. This phenomenon was used to determine dissociation constants and to estimate the rate of ligand dissociation. A Kd of 1 muM for maltose and of 0.16 muM for maltotroise was found. From the comparison of the kinetic parameters of transport of maltose and maltotriose in wild-type and lambda-resistant mutants with the binding constants for both sugars to purified maltose-binding protein, we conclude that the lambda receptor facilitates the diffusion of maltose and maltodextrins through the outer membrane.
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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 |
May
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pubmed:issn |
0014-2956
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
17
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pubmed:volume |
65
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
13-9
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pubmed:dateRevised |
2007-7-23
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pubmed:meshHeading |
pubmed-meshheading:776623-Bacterial Proteins,
pubmed-meshheading:776623-Binding Sites,
pubmed-meshheading:776623-Biological Transport, Active,
pubmed-meshheading:776623-Coliphages,
pubmed-meshheading:776623-Escherichia coli,
pubmed-meshheading:776623-Kinetics,
pubmed-meshheading:776623-Maltose,
pubmed-meshheading:776623-Mutation,
pubmed-meshheading:776623-Oligosaccharides,
pubmed-meshheading:776623-Protein Binding,
pubmed-meshheading:776623-Species Specificity,
pubmed-meshheading:776623-Spectrometry, Fluorescence
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pubmed:year |
1976
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pubmed:articleTitle |
Maltose transport in Escherichia coli K12. A comparison of transport kinetics in wild-type and lambda-resistant mutants as measured by fluorescence quenching.
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pubmed:publicationType |
Journal Article
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