Dear Barbara, yes, TRX reductase play an impoprtant role in ascoprbate recycling, I think that this role is much higher to xompare with tole of GSH.

Here is an link for this: http://www.sciencedirect.com/science/article/pii/S0076687902470322

One of the striking characteristics of TrxR is that it has low substrate specificity. TrxR can reduce not only oxidized Trx, but also dehydroascorbic acid, lipid hydroperoxides (ROOH), and α-lipoic acid. The other characteristic of TrxR is that it can direct reduce different protein disulfides, many low molecular weight disulfide compounds, and nondisulfide compounds. And many antioxidants can be regenerated by these reduction reactions; among them are selenium-containing enzymes and compounds, ascorbic acid (vitamin C), α-tocopherol (vitamin E), lipoic acid, and ubiquinone (coenzyme Q/Q10).

Thank you all for your input!

Dear Barbara,

  Dehydroascorbate (DHA) is spontaneously reduced by glutathione, and also by enzymic means, utilizing   glutathione or NADPH. Both mammalian thioltransferase (glutaredoxin) and protein disulfide isomerase possess DHA reductase activity. A separate DHA reductase activity from rat liver cytosol was characterized and purified; this enzyme identified with 3α-hydroxysteroid dehydrogenase. Another distinct rat liver cytosolic glutathione-dependent DHA reductase has also been purified and characterized.

Purified rat liver selenoenzyme, thioredoxin reductase (TrxR), directly functions as an NADPH-dependent dehydroascorbate reductase; this reductase employs NADPH to reduce DHA to ascorbate with a 1:1 stoichiometry.  The turn over number for DHA reduction by TrxR, with or without rat liver thioredoxin (Trx), was not different from that found for GSH-dependent DHA reduction by either human placental glutaredoxin or protein disulfide isomerase.  In comparison with either glutaredoxin or rat liver TrxR, a lesser role has been considered for rat liver 3α-hydroxysteroid dehydrogenase in reducing DHA. The broad substrate specificity of mammalian TrxRs is owing to a second redox-active site.