The role of chloride ions on the transport of glycine in plasma membrane vesicles from glial cells.
The high-affinity transport system for glycine in plasma membrane vesicles from C6 glioma cells is dependent on Na+ and also on the presence of Cl- in the incubation medium. This anion requirement is relatively specific for Cl-, since other anions are also capable of stimulating the glycine transport in the following order of decreasing efficacy: Cl- greater than Br- greater than SCN- congruent to I- greater than NO3- greater than F-. Chloride ions raise the Vmax for transport and, to a lesser extent, act on the Km. The data provided by direct measurements of the coupling of sodium and chloride to the transport of glycine by using a kinetic approach suggest a stoichiometry for the translocation cycle catalyzed by the glycine transporter of two sodium ions and one chloride ion per glycine zwitterion.
Zafra
F
F
Departamento de Bioloía Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain.
Giménez
C
C
D000838:Anions; D001254:Astrocytoma; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism*; D002712:Chlorides / Q000494:pharmacology*; D005998:Glycine / Q000378:metabolism*; D007700:Kinetics; D009457:Neuroglia / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000838:Anions; D002712:Chlorides; D012964:Sodium; D005998:Glycine