TY - JOUR
T1 - Glucose transporter isoforms GLUT1 and GLUT3 transport dehydroascorbic acid
AU - Rumsey, Steven C.
AU - Kwon, Oran
AU - Xu, Guo Wei
AU - Burant, Charles F.
AU - Simpson, Ian
AU - Levine, Mark
PY - 1997
Y1 - 1997
N2 - Dehydroascorbic acid (DHA) is rapidly taken up by cells and reduced to ascorbic acid (AA). Using the Xenopus laevis oocyte expression system we examined transport of DHA and AA via glucose transporter isoforms GLUT1-5 and SGLT1. The apparent K(m) of DHA transport via GLUT1 and GLUT3 was 1.1 ± 0.2 and 1.7 ± 0.3 mM, respectively. High performance liquid chromatography analysis confirmed 100% reduction of DHA to AA within oocytes. GLUT4 transport of DHA was only 2-4-fold above control and transport kinetics could not be calculated. GLUT2, GLUT5, and SGLT1 did not transport DHA and none of the isoforms transported AA. Radiolabeled sugar transport confirmed transporter function and identity of all cDNA clones was confirmed by restriction fragment mapping. GLUT1 and GLUT3 cDNA were further verified by polymerase chain reaction. DHA transport activity in both GLUT1 and GLUT3 was inhibited by 2-deoxyglucose, n-glucose, and 3-O-methylglucose among other hexoses while fructose and L-glucose showed no inhibition. Inhibition by the endofacial inhibitor, cytochalasin B, was non-competitive and inhibition by the exofacial inhibitor, 4,6-O-ethylidene-α-glucose, was competitive. Expressed mutant constructs of GLUT1 and GLUT3 did not transport DHA. DHA and 2-deoxyglucose uptake by Chinese hamster ovary cells overexpressing either GLUT1 or GLUT3 was increased 2-8-fold over control cells. These studies suggest GLUT1 and GLUT3 isoforms are the specific glucose transporter isoforms which mediate DHA transport and subsequent accumulation of AA.
AB - Dehydroascorbic acid (DHA) is rapidly taken up by cells and reduced to ascorbic acid (AA). Using the Xenopus laevis oocyte expression system we examined transport of DHA and AA via glucose transporter isoforms GLUT1-5 and SGLT1. The apparent K(m) of DHA transport via GLUT1 and GLUT3 was 1.1 ± 0.2 and 1.7 ± 0.3 mM, respectively. High performance liquid chromatography analysis confirmed 100% reduction of DHA to AA within oocytes. GLUT4 transport of DHA was only 2-4-fold above control and transport kinetics could not be calculated. GLUT2, GLUT5, and SGLT1 did not transport DHA and none of the isoforms transported AA. Radiolabeled sugar transport confirmed transporter function and identity of all cDNA clones was confirmed by restriction fragment mapping. GLUT1 and GLUT3 cDNA were further verified by polymerase chain reaction. DHA transport activity in both GLUT1 and GLUT3 was inhibited by 2-deoxyglucose, n-glucose, and 3-O-methylglucose among other hexoses while fructose and L-glucose showed no inhibition. Inhibition by the endofacial inhibitor, cytochalasin B, was non-competitive and inhibition by the exofacial inhibitor, 4,6-O-ethylidene-α-glucose, was competitive. Expressed mutant constructs of GLUT1 and GLUT3 did not transport DHA. DHA and 2-deoxyglucose uptake by Chinese hamster ovary cells overexpressing either GLUT1 or GLUT3 was increased 2-8-fold over control cells. These studies suggest GLUT1 and GLUT3 isoforms are the specific glucose transporter isoforms which mediate DHA transport and subsequent accumulation of AA.
UR - http://www.scopus.com/inward/record.url?scp=0030839797&partnerID=8YFLogxK
U2 - 10.1074/jbc.272.30.18982
DO - 10.1074/jbc.272.30.18982
M3 - Article
C2 - 9228080
AN - SCOPUS:0030839797
SN - 0021-9258
VL - 272
SP - 18982
EP - 18989
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 30
ER -