Luttik M A, Overkamp K M, Kötter P, de Vries S, van Dijken J P, Pronk J T
Department of Microbiology and Enzymology, Kluyver Institute of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
J Biol Chem. 1998 Sep 18;273(38):24529-34. doi: 10.1074/jbc.273.38.24529.
In Saccharomyces cerevisiae, the NDI1 gene encodes a mitochondrial NADH dehydrogenase, the catalytic side of which projects to the matrix side of the inner mitochondrial membrane. In addition to this NADH dehydrogenase, S. cerevisiae exhibits another mitochondrial NADH-dehydrogenase activity, which oxidizes NADH at the cytosolic side of the inner membrane. To investigate whether open reading frames YMR145c/NDE1 and YDL 085w/NDE2, which exhibit sequence similarity with NDI1, encode the latter enzyme, NADH-dependent mitochondrial respiration was assayed in wild-type S. cerevisiae and nde deletion mutants. Mitochondria were isolated from aerobic, glucose-limited chemostat cultures grown at a dilution rate (D) of 0. 10 h-1, in which reoxidation of cytosolic NADH by wild-type cells occurred exclusively by respiration. Compared with the wild type, rates of mitochondrial NADH oxidation were about 3-fold reduced in an nde1Delta mutant and unaffected in an nde2Delta mutant. NADH-dependent mitochondrial respiration was completely abolished in an nde1Delta nde2Delta double mutant. Mitochondrial respiration of substrates other than NADH was not affected in nde mutants. In shake flasks, an nde1Delta nde2Delta mutant exhibited reduced specific growth rates on ethanol and galactose but not on glucose. Glucose metabolism in aerobic, glucose-limited chemostat cultures (D = 0.10 h-1) of an nde1Delta nde2Delta mutant was essentially respiratory. Apparently, under these conditions alternative systems for reoxidation of cytosolic NADH could replace the role of Nde1p and Nde2p in S. cerevisiae.
在酿酒酵母中，NDI1基因编码一种线粒体NADH脱氢酶，其催化侧伸向线粒体内膜的基质侧。除了这种NADH脱氢酶外，酿酒酵母还表现出另一种线粒体NADH脱氢酶活性，该活性在内膜的胞质侧氧化NADH。为了研究与NDI1具有序列相似性的开放阅读框YMR145c/NDE1和YDL 085w/NDE2是否编码后一种酶，在野生型酿酒酵母和nde缺失突变体中测定了NADH依赖性线粒体呼吸。从以0.10 h-1的稀释率（D）生长的好氧、葡萄糖限制恒化器培养物中分离出线粒体，在该培养物中野生型细胞通过呼吸专门进行胞质NADH的再氧化。与野生型相比，nde1Δ突变体中线粒体NADH氧化速率降低了约3倍，而nde2Δ突变体中不受影响。在nde1Δnde2Δ双突变体中，NADH依赖性线粒体呼吸完全被消除。nde突变体中除NADH外的其他底物的线粒体呼吸不受影响。在摇瓶中，nde1Δnde2Δ突变体在乙醇和半乳糖上的比生长速率降低，但在葡萄糖上没有降低。nde1Δnde2Δ突变体在好氧、葡萄糖限制恒化器培养物（D = 0.10 h-1）中的葡萄糖代谢基本上是呼吸性的。显然，在这些条件下，胞质NADH再氧化的替代系统可以取代酿酒酵母中Nde1p和Nde2p的作用。
