The membrane transport of ascorbic acid.
A system for measuring the rate of transport of dehydroascorbate into human red blood cells shows Michaelis-Menten type kinetics with substrate inhibition at levels above 150 muM DHA. The addition of sugars impairs this transport in the diminishing hierarchy D-glucose, D-mannose, D-xylose, D-galactose, L-lyxose, D-araboascorbate, L-sorbose and 2-deoxy-D-ribose. The effect of glucose on transport of ascorbate is marked at physiological levels. Transport of DHA is accelerated by copper ion and allows dehydroascorbate to move against a concentration gradient. The evidence supports the hypotheses proposing that hyperglycemia will impair the intracellular availability of vitamin C.
D000328:Adult; D001205:Ascorbic Acid / Q000097:blood*; D001693:Biological Transport, Active; D002248:Carbon Monoxide / Q000097:blood; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002570:Ceruloplasmin / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D003683:Dehydroascorbic Acid / Q000097:blood / Q000494:pharmacology; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D006601:Hexoses / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D010429:Pentoses / Q000494:pharmacology
D006601:Hexoses; D010429:Pentoses; D003300:Copper; D002248:Carbon Monoxide; D002570:Ceruloplasmin; D005947:Glucose; D001205:Ascorbic Acid; D003683:Dehydroascorbic Acid