Generating disulfides enzymatically: Reaction products and electron acceptors of the endoplasmic reticulum thiol oxidase Ero1p
Generating disulfides enzymatically: Reaction products and electron acceptors of the endoplasmic reticulum thiol oxidase Ero1p
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DOI：
10.1073/pnas.0506448103
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发表时间：
2006-01-10
影响因子：
11.1
通讯作者：
Fass, D
中科院分区：
文献类型：
--
作者：
Gross, E;Sevier, CS;Fass, D
Ero1p是真核细胞在有氧和厌氧环境中二硫键形成途径中的关键酶。以前证明Ero1p可以将电子从硫醇底物转移到分子氧。然而，在厌氧条件下电子的命运和有氧条件下电子的最终命运仍然不清楚。为了解决Ero1p机制中的这些基本问题，我们研究了电子从重组酵母Ero1p到各种电子受体的转移。在有氧条件下，通过Ero1p还原分子氧产生化学计量的过氧化氢。值得注意的是，我们发现，减少Ero1p可以转移电子到各种小的和大分子的电子受体，除了分子氧。特别是，Ero1p可以催化溶液中外源性FAD的还原。Ero1p催化二硫醇氧化不需要游离FAD，但它足以在厌氧条件下驱动二硫键形成。这些发现提供了深入了解再生氧化Ero1p和维持二硫键形成的内质网在厌氧条件下的机制。
Ero1p is a key enzyme in the disulfide bond formation pathway in eukaryotic cells in both aerobic and anaerobic environments. It was previously demonstrated that Ero1p can transfer electrons from thiol substrates to molecular oxygen. However, the fate of electrons under anaerobic conditions and the final fate of electrons under aerobic conditions remained obscure. To address these fundamental issues in the Ero1p mechanism, we studied the transfer of electrons from recombinant yeast Ero1p to various electron acceptors. Under aerobic conditions, reduction of molecular oxygen by Ero1p yielded stoichiometric hydrogen peroxide. Remarkably, we found that reduced Ero1p can transfer electrons to a variety of small and macromolecular electron acceptors in addition to molecular oxygen. In particular, Ero1p can catalyze reduction of exogenous FAD in solution. Free FAD is not required for the catalysis of dithiol oxidation by Ero1p, but it is sufficient to drive disulfide bond formation under anaerobic conditions. These findings provide insight into mechanisms for regenerating oxidized Ero1p and maintaining disulfide bond formation under anaerobic conditions in the endoplasmic reticulum.