Mitochondrial uptake and recycling of ascorbic acid.

Li X, Cobb CE, Hill KE, Burk RF, May JM
Arch Biochem Biophys. 2001 387 (1): 143-53

PMID: 11368176 · DOI:10.1006/abbi.2000.2245

Mitochondria generate reactive oxygen species as by-products of oxidative metabolism. Since ascorbic acid can scavenge such destructive species, we studied the ability of mitochondria from rat liver and muscle to take up, recycle, and oxidize ascorbate. Freshly prepared mitochondria contain ascorbate, as do mitoplasts that lack the outer mitochondrial membrane. Both mitochondria and mitoplasts rapidly take up oxidized ascorbate as dehydroascorbic acid and reduce it to ascorbate. Ascorbate concentrations in mitochondria and mitoplasts rise into the low millimolar range during dehydroascorbic acid uptake, although uptake and reduction is opposed by ascorbate efflux. Mitochondrial dehydroascorbic acid reduction depends mainly on GSH, but mitochondrial thioredoxin reductase may also contribute. Reactive oxygen species generated within mitochondria oxidize ascorbate more readily than they do GSH and alpha-tocopherol. These results show that mitochondria can recycle ascorbate, which in turn might help to prevent deleterious effects of oxidant stress in the organelle.

MeSH Terms (11)

Animals Ascorbic Acid Biological Transport Dehydroascorbic Acid Glutathione Male Mitochondria, Liver Mitochondria, Muscle Oxidation-Reduction Rats Submitochondrial Particles

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