Abstract
The present data confirmed previous studies with other cell types that ascorbic acid and dehydroascorbic acid are transported through different transporters into SV-40-transformed retinal pigment epithelial cells. These experiments were performed on cells grown on 96-well culture plates. Ascorbic acid was taken up into the cell by a high-affinity transporter with Km = 0.041 mmol/1 and a low Vmax of 2.74 pmol/min/well. Dehydroascorbic acid was taken up by a low-affinity transporter with Km = 5.67 mmol/1; however, the Vmax was 325.5 pmol/min/well. The uptake of both ascorbic acid and dehydroascorbic acid was dependent on the sodium concentration. The uptake of ascorbic acid does not involve oxidation-reaction steps because the uptake of [l4C]-ascorbate was unaffected by the presence of an excess amount of unlabelled dehydroascorbic acid.
Original language | English (US) |
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Pages (from-to) | 100-107 |
Number of pages | 8 |
Journal | Ophthalmic Research |
Volume | 25 |
Issue number | 2 |
DOIs | |
State | Published - 1993 |
Keywords
- Active transport
- Ascorbate
- Dehydroascorbate
- Oxidative reduction
- Retinal pigment epithelium
- Sodium
ASJC Scopus subject areas
- Ophthalmology
- Sensory Systems
- Cellular and Molecular Neuroscience