Komuniecki R, McCrury J, Thissen J, Rubin N
Department of Biology, University of Toledo, OH 43606.
Biochim Biophys Acta. 1989 Jun 23;975(1):127-31. doi: 10.1016/s0005-2728(89)80210-5.
Electron-transfer flavoprotein was purified to apparent homogeneity from mitochondria of the parasitic nematode, Ascaris suum. The native molecular weight of the enzyme was 70,000, as estimated by gel filtration, and it migrated as two bands with apparent subunit molecular weights of 37,000 and 31,500 during sodium dodecylsulfate polyacrylamide gel electrophoresis. The enzyme exhibited an absorption coefficient for the bound FAD of 13.5 mM-1.cm-1 at 436 nm and a protein/flavin (270 nm/436 nm) ratio of 5.6. While the ascarid enzyme is similar to its mammalian counterpart, physiologically it functions in the reverse direction, shuttling reducing power from the electron-transport chain to a soluble 2-methyl branched-chain enoyl CoA reductase. Indeed, when A. suum submitochondrial particles were incubated with NADH, 2-methylcrotonyl-CoA and purified A. suum 2-methyl branched-chain enoyl-CoA reductase, 2-methylbutyryl-CoA formation was proportional to the amount of electron-transfer flavoprotein added.
从寄生线虫猪蛔虫的线粒体中纯化出了具有明显均一性的电子传递黄素蛋白。通过凝胶过滤估计，该酶的天然分子量为70,000，在十二烷基硫酸钠聚丙烯酰胺凝胶电泳过程中，它迁移为两条带，其表观亚基分子量分别为37,000和31,500。该酶在436nm处结合FAD的吸收系数为13.5mM-1.cm-1，蛋白质/黄素（270nm/436nm）的比率为5.6。虽然蛔虫的这种酶与其哺乳动物对应物相似，但在生理功能上它的作用方向相反，将还原力从电子传递链穿梭到可溶性2-甲基支链烯酰辅酶A还原酶。实际上，当猪蛔虫亚线粒体颗粒与NADH、2-甲基巴豆酰辅酶A和纯化的猪蛔虫2-甲基支链烯酰辅酶A还原酶一起孵育时，2-甲基丁酰辅酶A的形成与添加的电子传递黄素蛋白的量成正比。
