The influence of zinc(II) on thioredoxin/glutathione disulfide exchange: QM/MM studies to explore how zinc(II) accelerates exchange in higher dielectric environments.

QM/MM studies were performed to explore the energetics of exchange reactions of glutathione disulfide (GSSG) and the active site of thioredoxin [Cys32-Gly33-Pro34-Cys35] with and without zinc(II), in vacuum and solvated models. The activation energy for exchange, in the absence of zinc, is 29.7 kcal mol(-1) for the solvated model.