Linked Life Data

7964387

Source:http://linkedlifedata.com/resource/pubmed/id/7964387

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1994-12-7
pubmed:abstractText
The time-dependent fluorescence intensity of an intravesicular potential-sensitive dye was used to probe the real-time kinetics of potential difference (PD)-dependent amino acid/Na+ symport at pH9 into brush-border membrane vesicles obtained from larval Manduca sexta midgut. Neutral amino acids (alanine, proline) are symported at higher rates as the vesicles are hyperpolarized. The symport rates of acidic (glutamate) and basic (arginine) amino acids are almost PD-independent. The half-saturation constant of alanine is PD-independent between -108 and -78 mV, although the maximal symport velocity increases by half as the voltage is increased. Amino acid throughput is evidently enhanced as the relatively high transmembrane PDs (> 150 mV, lumen positive) measured in vivo are approached. The half-saturation concentrations of Na+ were in the range 15-40 mmol l-1 for most of the amino acids examined and increased with voltage for alanine. The Vmax observed as a function of cation or amino acid concentration increased as the vesicle was hyperpolarized in the case of leucine and alanine. The data support the hypothesis that carrier and substrates are at equilibrium inasmuch as substrate translocation seems to be the rate-determining step of symport.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-0949
pubmed:author
pubmed:issnType
Print
pubmed:volume
189
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
55-67
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Potential differences influence amino acid/Na+ symport rates in larval Manduca sexta midgut brush-border membrane vesicles.
pubmed:affiliation
Department of Biology, Temple University, Philadelphia, PA 19122.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.