Enzymes
| UniProtKB help_outline | 476 proteins |
Reaction participants Show >> << Hide
- Name help_outline L-cysteine Identifier CHEBI:35235 Charge 0 Formula C3H7NO2S InChIKeyhelp_outline XUJNEKJLAYXESH-REOHCLBHSA-N SMILEShelp_outline [NH3+][C@@H](CS)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 71 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline L-phenylalanine Identifier CHEBI:58095 Charge 0 Formula C9H11NO2 InChIKeyhelp_outline COLNVLDHVKWLRT-QMMMGPOBSA-N SMILEShelp_outline [NH3+][C@@H](Cc1ccccc1)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 78 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:71031 | RHEA:71032 | RHEA:71033 | RHEA:71034 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Activation of system L heterodimeric amino acid exchangers by intracellular substrates.
Meier C., Ristic Z., Klauser S., Verrey F.
System L-type transport of large neutral amino acids is mediated by ubiquitous LAT1-4F2hc and epithelial LAT2-4F2hc. These heterodimers are thought to function as obligatory exchangers, but only influx properties have been studied in some detail up until now. Here we measured their intracellular s ... >> More
System L-type transport of large neutral amino acids is mediated by ubiquitous LAT1-4F2hc and epithelial LAT2-4F2hc. These heterodimers are thought to function as obligatory exchangers, but only influx properties have been studied in some detail up until now. Here we measured their intracellular substrate selectivity, affinity and exchange stoichiometry using the Xenopus oocyte expression system. Quantification of amino acid influx and efflux by HPLC demonstrated an obligatory amino acid exchange with 1:1 stoichiometry. Strong, differential trans-stimulations of amino acid influx by injected amino acids showed that the intracellular substrate availability limits the transport rate and that the efflux selectivity range resembles that of influx. Compared with high extracellular apparent affinities, LAT1- and LAT2-4F2hc displayed much lower intracellular apparent affinities (apparent K(m) in the millimolar range). Thus, the two system L amino acid transporters that are implicated in cell growth (LAT1-4F2hc) and transcellular transport (LAT2-4F2hc) are obligatory exchangers with relatively symmetrical substrate selectivities but strongly asymmetrical substrate affinities such that the intracellular amino acid concentration controls their activity. << Less
EMBO J. 21:580-589(2002) [PubMed] [EuropePMC]
This publication is cited by 10 other entries.