EFFECTS OF ASCORBATE AND ATP UPON AMINO-ACID-TRANSPORT IN TOADS CORNEA

  • 1 January 1978
    • journal article
    • research article
    • Vol. 17  (4) , 370-373
Abstract
The effects of ascorbate upon amino acid uptake were examined in the in vitro toad [Bufo marinus] cornea. Physiologic levels of ascorbate increased the uptake of leucine by approximately 35% but had no effect upon the uptake of alanine. Uncouplers of oxidative phosphorylation did not inhibit the stimulation by ascorbic acid of leucine accumulation, indicating the increased synthesis of ATP was not the mechanism; exogenous ATP, unlike ascorbate, stimulated the uptake of both alanine and leucine. CO blocked the effects of ascorbate, whereas 2-heptyl-4-hydroxyquinoline-N-oxide (HOQNO), which inhibited reverse electron transfer, enhanced the accumulation of leucine. Ascorbate may serve as an energy source for the uptake of leucine.

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