| http://purl.uniprot.org/citations/17012227 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/17012227 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/17012227 | http://www.w3.org/2000/01/rdf-schema#comment | "We characterized the human Na(+)-ascorbic acid transporter SVCT2 and developed a basic model for the transport cycle that challenges the current view that it functions as a Na(+)-dependent transporter. The properties of SVCT2 are modulated by Ca(2+)/Mg(2+) and a reciprocal functional interaction between Na(+) and ascorbic acid that defines the substrate binding order and the transport stoichiometry. Na(+) increased the ascorbic acid transport rate in a cooperative manner, decreasing the transport K(m) without affecting the V(max), thus converting a low affinity form of the transporter into a high affinity transporter. Inversely, ascorbic acid affected in a bimodal and concentration-dependent manner the Na(+) cooperativity, with absence of cooperativity at low and high ascorbic acid concentrations. Our data are consistent with a transport cycle characterized by a Na(+):ascorbic acid stoichiometry of 2:1 and a substrate binding order of the type Na(+):ascorbic acid:Na(+). However, SVCT2 is not electrogenic. SVCT2 showed an absolute requirement for Ca(2+)/Mg(2+) for function, with both cations switching the transporter from an inactive into an active conformation by increasing the transport V(max) without affecting the transport K(m) or the Na(+) cooperativity. Our data indicate that SVCT2 may switch between a number of states with characteristic properties, including an inactive conformation in the absence of Ca(2+)/Mg(2+). At least three active states can be envisioned, including a low affinity conformation at Na(+) concentrations below 20 mM and two high affinity conformations at elevated Na(+) concentrations whose Na(+) cooperativity is modulated by ascorbic acid. Thus, SVCT2 is a Ca(2+)/Mg(2+)-dependent transporter."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.org/dc/terms/identifier | "doi:10.1074/jbc.M608300200"xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.org/dc/terms/identifier | "doi:10.1074/jbc.m608300200"xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Reyes A.M."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Carcamo J."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Reyes A."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Aguayo L.G."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Moraga-Cid G."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Vera J.C."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Vera J.C."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Onate S.A."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Ormazabal V."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Ormazabal V."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Zuniga F.A."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Zuniga F.A."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Guzman C."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Guzman C."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Vasquez O."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Vasquez O."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Aguayo L."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Barra V."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Barra V."xsd:string |
| http://purl.uniprot.org/citations/17012227 | http://purl.uniprot.org/core/author | "Godoy A."xsd:string |