Cottingham I R, Moore A L
Biochem J. 1984 Nov 15;224(1):171-9. doi: 10.1042/bj2240171.
The external NADH dehydrogenase has been purified from Arum maculatum (cuckoo-pint) mitochondria by phosphate washing, extraction with deoxycholate, ion-exchange and gel-filtration chromatography. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis shows, when the gel is silver-stained, that the purified enzyme contains two major bands of Mr 78 000 and 65 000 and a minor one of Mr about 76 000. It is not possible at present to determine which of these, or which combination, constitutes the dehydrogenase. The enzyme contains non-covalently bound FAD and a small amount of FMN. Since the conditions of purification lead to considerable loss of flavin and possibly iron-sulphur centres, it is not possible to decide with certainty whether the enzyme is a flavo- or ferroflavo-protein. The enzyme has been distinguished from the other NADH dehydrogenases on the basis of its substrate specificity, its capability of reducing electron acceptors such as ubiquinone-1 and 2,6-dichlorophenol-indophenol and its sensitivity towards Ca2+, EGTA and dicoumarol.
已通过磷酸盐洗涤、脱氧胆酸盐提取、离子交换和凝胶过滤色谱法从斑叶疆南星（斑叶阿若母）线粒体中纯化出外部NADH脱氢酶。用十二烷基硫酸钠/聚丙烯酰胺凝胶电泳法，银染凝胶时显示，纯化后的酶含有两条主要条带，分子量分别为78000和65000，还有一条分子量约为76000的次要条带。目前无法确定这些条带中的哪一条，或哪几种组合构成了脱氢酶。该酶含有非共价结合的FAD和少量FMN。由于纯化条件会导致黄素以及可能的铁硫中心大量损失，因此无法确定该酶是黄素蛋白还是铁黄素蛋白。基于其底物特异性、还原电子受体（如泛醌-1和2,6-二氯酚靛酚）的能力以及对Ca2+、乙二醇双四乙酸和双香豆素的敏感性，该酶已与其他NADH脱氢酶区分开来。
