Passive and carrier-mediated permeation of different nucleosides through the reconstituted nucleoside transporter

Chung Ming Tse, James D. Young

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

When reconstituted into proteoliposomes, the human erythrocyte nucleoside transporter catalysed nitrobenzylthioguanosine (NBTGR)-sensitive zero-trans influx of three different nucleosides at broadly similar rates (inosine, uridine > adenosine). However, proteoliposomes also exhibited high rates of NBTGR-insensitive uptake of adenosine, making this nucleoside unsuitable for reconstitution studies. Equivalent high rates of adenosine influx were observed in protein-free liposomes, establishing that this permeability pathway represents simple diffusion of nucleoside across the lipid bilayer. In contrast to adenosine, inosine and uridine exhibited acceptable rates of NBTGR-insensitive uptake. Of the two, inosine is the more attractive permeant for reconstitution experiments, having a 2.5-fold lower basal membrane permeability. Studies of nucleoside transport specificity in reconstituted membrane vesicles should take account of the widely different passive permeabilities of different nucleosides.

Original languageEnglish (US)
Pages (from-to)343-346
Number of pages4
JournalBBA - Biomembranes
Volume985
Issue number3
DOIs
StatePublished - Nov 3 1989
Externally publishedYes

Keywords

  • (Human erythrocyte)
  • Nucleoside transport
  • Reconstitution

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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