Human erythrocytes transport dehydroascorbic acid and sugars using the same transporter complex

Am J Physiol Cell Physiol. 2014 May 15;306(10):C910-7. doi: 10.1152/ajpcell.00044.2014. Epub 2014 Mar 5.


GLUT1, the primary glucose transport protein in human erythrocytes [red blood cells (RBCs)], also transports oxidized vitamin C [dehydroascorbic acid (DHA)]. A recent study suggests that RBC GLUT1 transports DHA as its primary substrate and that only a subpopulation of GLUT1 transports sugars. This conclusion is based on measurements of cellular glucose and DHA equilibrium spaces, rather than steady-state transport rates. We have characterized RBC transport of DHA and 3-O-methylglucose (3-OMG), a transported, nonmetabolizable sugar. Steady-state 3-OMG and DHA uptake in the absence of intracellular substrate are characterized by similar Vmax (0.16 ± 0.01 and 0.13 ± 0.02 mmol·l(-1)·min(-1), respectively) and apparent Km (1.4 ± 0.2 and 1.6 ± 0.7 mM, respectively). 3-OMG and DHA compete for uptake, with Ki(app) of 0.7 ± 0.4 and 1.1 ± 0.1 mM, respectively. Uptake measurements using RBC inside-out-membrane vesicles demonstrate that 3-OMG and DHA compete at the cytoplasmic surface of the membrane, with Ki(app) of 0.7 ± 0.1 and 0.6 ± 0.1 mM, respectively. Intracellular 3-OMG stimulates unidirectional uptake of 3-OMG and DHA. These findings indicate that DHA and 3-OMG bind at mutually exclusive sites at exo- and endofacial surfaces of GLUT1 and are transported via the same GLUT1 complex.

Keywords: GLUT1; dehydroascorbic acid transport; erythrocyte; glucose transport.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3-O-Methylglucose / metabolism*
  • Binding Sites
  • Binding, Competitive
  • Biological Transport
  • Carbon Radioisotopes
  • Dehydroascorbic Acid / metabolism*
  • Erythrocyte Membrane / metabolism*
  • Glucose / metabolism*
  • Glucose Transporter Type 1 / metabolism*
  • Humans
  • Kinetics
  • Protein Binding
  • Tritium


  • Carbon Radioisotopes
  • Glucose Transporter Type 1
  • SLC2A1 protein, human
  • Tritium
  • 3-O-Methylglucose
  • Glucose
  • Dehydroascorbic Acid