Enzymes
| UniProtKB help_outline | 3 proteins |
Reaction participants Show >> << Hide
- Name help_outline 4-hydroxy-L-proline Identifier CHEBI:58419 Charge 0 Formula C5H9NO3 InChIKeyhelp_outline PMMYEEVYMWASQN-BKLSDQPFSA-N SMILEShelp_outline OC1C[NH2+][C@@H](C1)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline Na+ Identifier CHEBI:29101 (CAS: 17341-25-2) help_outline Charge 1 Formula Na InChIKeyhelp_outline FKNQFGJONOIPTF-UHFFFAOYSA-N SMILEShelp_outline [Na+] 2D coordinates Mol file for the small molecule Search links Involved in 259 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:70023 | RHEA:70024 | RHEA:70025 | RHEA:70026 | |
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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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Transport of proline and hydroxyproline by the neutral amino-acid exchanger ASCT1.
Pinilla-Tenas J., Barber A., Lostao M.P.
ASCT1 is a member of the glutamate transporter superfamily cloned from human brain and characterized as a Na(+)-dependent neutral amino-acid exchanger, which displays substrate-induced chloride-channel activity and mediates concentrative transport of alanine. Initial studies in ASCT1-expressing Xe ... >> More
ASCT1 is a member of the glutamate transporter superfamily cloned from human brain and characterized as a Na(+)-dependent neutral amino-acid exchanger, which displays substrate-induced chloride-channel activity and mediates concentrative transport of alanine. Initial studies in ASCT1-expressing Xenopus laevis oocytes showed that proline did not elicit measurable currents, in contrast to what occurred with alanine, serine or cysteine, suggesting that proline was not an ASCT1 substrate, although it induced the release of alanine from preloaded oocytes. Here, we have studied the uptake of proline and hydroxyproline by ASCT1-expressing oocytes in order to investigate the ability of ASCT1 to translocate these imino acids. The results demonstrate ASCT1-mediated proline transport that is Na(+)-dependent, saturable, inhibited by the reported ASCT1 substrates as well as by hydroxyproline and can drive the imino acid against its concentration gradient. The apparent kinetic constants for the transport of alanine and the imino acids, obtained with oocytes from the same batch, showed maximal transport rate for proline and hydroxyproline to be half of that for alanine. However, K(0.5) for proline was 704 +/-86 microM, about three times higher than alanine K(0.5) (203.3 +/-36.4 microM), whereas hydroxyproline K(0.5) was 33.2 +/-4.3 microM, indicating that the hydroxylation on carbon 4 of proline strongly increases the affinity of ASCT1 for this proline derivative. In summary, the present work demonstrates for the first time the ability of ASCT1 to transport proline and hydroxyproline. << Less
J. Membr. Biol. 195:27-32(2003) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.