Suh J K, Poulsen L L, Ziegler D M, Robertus J D
Institute of Cellular and Molecular Biology, Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA.
Proc Natl Acad Sci U S A. 1999 Mar 16;96(6):2687-91. doi: 10.1073/pnas.96.6.2687.
The flavin-containing monooxygenase from yeast (yFMO) catalyzes the O2- and NADPH-dependent oxidations of biological thiols, including oxidation of glutathione to glutathione disulfide (GSSG). Glutathione and GSSG form the principle redox buffering system in the cell, with the endoplasmic reticulum (ER) being more oxidizing than the cytoplasm. Proper folding of disulfide-bonded proteins in the ER depends on an optimum redox buffer ratio. Here we show that yFMO is localized to the cytoplasmic side of the ER membrane. We used a gene knockout strain and expression vectors to show that yFMO has a major effect on the generation of GSSG transported into the ER. The enzyme is required for the proper folding, in the ER, of test proteins with disulfide bonds, whereas those without disulfide bonds are properly folded independently of yFMO in the ER or in the cytoplasm.
来自酵母的含黄素单加氧酶（yFMO）催化生物硫醇的O2和NADPH依赖性氧化，包括将谷胱甘肽氧化为谷胱甘肽二硫化物（GSSG）。谷胱甘肽和GSSG构成细胞中的主要氧化还原缓冲系统，内质网（ER）比细胞质氧化性更强。ER中含二硫键蛋白质的正确折叠取决于最佳氧化还原缓冲比。在这里，我们表明yFMO定位于ER膜的细胞质一侧。我们使用基因敲除菌株和表达载体表明yFMO对转运到ER中的GSSG的生成有重大影响。该酶是ER中具有二硫键的测试蛋白正确折叠所必需的，而没有二硫键的蛋白在ER或细胞质中独立于yFMO正确折叠。
