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Titolo:
THE BINDING-SPECIFICITY OF AMINO-ACID-TRANSPORT SYSTEM Y(+)L IN HUMANERYTHROCYTES IS ALTERED BY MONOVALENT CATIONS
Autore:
ANGELO S; IRARRAZABAL C; DEVES R;
Indirizzi:
UNIV CHILE,FAC MED,DEPT PHYSIOL & BIOPHYS SANTIAGO 7 CHILE UNIV CHILE,FAC MED,DEPT PHYSIOL & BIOPHYS SANTIAGO 7 CHILE
Titolo Testata:
The Journal of membrane biology
fascicolo: 1, volume: 153, anno: 1996,
pagine: 37 - 44
SICI:
0022-2631(1996)153:1<37:TBOASY>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT-KIDNEY; EXPRESSION CLONING; MOUSE BLASTOCYSTS; PLASMA-MEMBRANE; HEAVY-CHAIN; DEPENDENCE; RECEPTOR; CYSTINE; OOCYTES; ANTIGEN;
Keywords:
LYSINE; TRANSPORT; AMINO ACIDS; CARRIER; SPECIFICITY; SYSTEM Y(+)L;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
27
Recensione:
Indirizzi per estratti:
Citazione:
S. Angelo et al., "THE BINDING-SPECIFICITY OF AMINO-ACID-TRANSPORT SYSTEM Y(+)L IN HUMANERYTHROCYTES IS ALTERED BY MONOVALENT CATIONS", The Journal of membrane biology, 153(1), 1996, pp. 37-44

Abstract

System y(+)L is a broad-scope amino acid transporter which binds and translocates cationic and neutral amino acids. Na+ replacement with Kdoes not affect lysine transport, but markedly decreases the affinityof the transporter for L-leucine and L-glutamine. This observation suggests that the specificity of system y(+)L varies depending on the ionic composition of the medium. Here we have studied the interaction ofthe carrier with various amino acids in the presence of Na+, K+, Li+ and guanidinium ion. In agreement with the prediction, the specificityof system y(+)L was altered by the monovalent cations. In the presence of Na+, L-leucine was the neutral amino acid that interacted more powerfully. Elongation of the side chain (glycine-L-norleucine) strengthened binding. In contrast, bulkiness at the level of the beta carbon was detrimental. In K+, the carrier behaved as a cationic amino acid specific carrier, interacting weakly with neutral amino acids. Li+ was found to potentiate neutral amino acid binding and in general the apparent affinities were higher than in Na+; elongation of the nonpolar side chain made a more important contribution to binding and the carrier was more tolerant towards beta carbon substitution. Guanidinium stimulated the interaction of the carrier with neutral amino acids, but the effect was restricted to certain analogues (e.g., L-leucine, L-glutamine, L-methionine). Thus, in the presence of guanidinium, the carrier discriminates sharply among different neutral amino acids. The results suggest that the monovalent cations stabilize different carrier conformations.

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Documento generato il 28/01/21 alle ore 07:44:35