Linked Life Data

1034640

Source:http://linkedlifedata.com/resource/pubmed/id/1034640

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1977-3-21
pubmed:abstractText
The carrier of uridine transport in hamster cells in culture is highly susceptible to the inhibitory effect of probes like S-benzylated derivatives of mercaptopurine nucleosides. The interaction between the probes and the carrier is competitive and reversible and it takes place at a site different from the substrate binding site. The Ki for the most potent derivative p-nitrobenzyl-6-mercaptoinosine is 0.15 n Molar at 20 degrees C. The effect of the probes is interpreted in terms of conformational change induced on the carrier upon binding of the probe. The carrier assumes distinct conformations depending on whether it is probe-free (form A) or probe bound (form B). Kinetic as well as chemical evidence supports the predictions of the allosteric carrier model. A single component of kinetics is observed either in the absence of inhibitor (Km form A) or at high concentrations of inhibitor (Km form B). A two component kinetics is observed at intermediate concentrations of inhibitor (some carriers in form B and others in form A). The two forms have distinct Km values for uridine: form A50 muMolar and form B 250 muMolar. Two forms have also different susceptibilities to the action of organomercurials: form A is insensitive whereas form B is highly inhibited by the chemical modified of SH groups. The existence of putative allosteric sites in carriers is discussed in terms of modifier sites capable of modulating transport activities as a result of specific membrane-ligand interactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9541
pubmed:author
pubmed:issnType
Print
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
831-8
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
The mechanism of interaction between high-affinity probes and the uridine transport system of mammalian cells.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.