Linked Life Data

9568481

Source:http://linkedlifedata.com/resource/pubmed/id/9568481

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-6-4
pubmed:abstractText
The properties are discussed of system y+L, a broad scope amino acid transporter which was first identified in human erythrocytes. System y+L exhibits two distinctive properties: (a) it can bind and translocate cationic and neutral amino acids, and (b) its specificity varies depending on the ionic composition of the medium. In Na+ medium, the half-saturation constant for L-lysine influx was 9.5 +/- 0.67 microM and the inhibition constant (Ki) for L-leucine was 10.7 +/- 0.72 microM. L-Leucine is the neutral amino acid that binds more powerfully, whereas smaller analogues, such as L-alanine and L-serine interact less strongly (the corresponding inhibition constants were Ki,Ala, 0.62 +/- 0.11 mM; Ki,Ser, 0.49 +/- 0.08 mM). In the presence of K+, the carrier functions as a cationic amino acid specific carrier, but Li+ is able to substitute for Na+ facilitating neutral amino acid binding. The effect of the inorganic cations is restricted to the recognition of neutral amino acids; translocation occurs at similar rates in the presence of Na+, K+ and Li+. The only structural feature that appears to impair translocation is bulkiness and substrates with half-saturation constants differing by more than 100-fold translocate at the same rate. This suggests that translocation is largely independent of the forces of interaction between the substrate and the carrier site. System y+L activity has been observed in Xenopus laevis oocytes injected with the cRNA for the heavy chain of the 4F2 human surface antigen. 4F2hc is an integral membrane protein with a single putative membrane-spanning domain and it remains to be clarified whether it is part of the transporter or an activator protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0958-0670
pubmed:author
pubmed:issnType
Print
pubmed:volume
83
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
211-20
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
System y+L: the broad scope and cation modulated amino acid transporter.
pubmed:affiliation
Programa de Fisiología y Biofísica, Facultad de Medicina, Universidad de Chile, Santiagó, Chile. rdeves@bitmed.med.uchile.cl
pubmed:publicationType
Journal Article, In Vitro, Review, Research Support, Non-U.S. Gov't