Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1976-9-2
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13-9
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1976
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.
pubmed:publicationType
Journal Article