Carrier mediated uptake of dehydroascorbate into higher plant plasma membrane vesicles shows trans‐stimulation

FEBS Letters

Horemans, Nele¹  Asard, Han¹  Caubergs, Roland Julien¹ 

[1] Department of Biology, University of Antwerp (RUCA), Groenenborgerlaan 171, B-2020 Antwerp, Belgium

关键词: Ascorbate;    Plasma membrane;    Ascorbate transport;    Ascorbate/dehydroascorbate carrier;    Counterflow;    Phaseolus;   

DOI  :  10.1016/S0014-5793(97)01534-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The activity of the ascorbate (Asc) carrier of purified Phaseolus plasma membranes is demonstrated to be highly stimulated when membrane vesicles are preloaded with Asc. Asc transport is inhibited by DTT but is not affected by glutathione or ferricyanide, indicating that dehydroascorbate (DHA) is the preferred species for uptake. Asc transport in the loaded vesicles showed saturable kinetics with an apparent affinity constant of 24 μM and maximal uptake rate of 94 pmol/mg/min. Addition of DHA stimulated the efflux of Asc molecules from the loaded vesicles. Together these results suggest the presence of an Asc/DHA exchange mechanism in higher plant plasma membranes.

【 授权许可】

Unknown