该基因编码的蛋白属于复合物I 75 kDa亚基家族哺乳动物复合体i由45个不同的亚单位组成。它位于线粒体内膜该蛋白具有NADH脱氢酶活性和氧化还原酶活性。它将电子从nadh转移到呼吸链。酶的直接电子受体被认为是泛醌。该蛋白是复合物i的最大亚单位，是酶的铁硫（ip）片段的组成部分。它可以形成NADH氧化的活性部位缝隙的一部分。这个基因的突变与复杂的i缺乏症有关。已经发现了一些编码不同亚型的转录变体。[由RefSeq提供，2011年1月]
The protein encoded by this gene belongs to the complex I 75 kDa subunit family. Mammalian complex I is composed of 45 different subunits. It locates at the mitochondrial inner membrane. This protein has NADH dehydrogenase activity and oxidoreductase activity. It transfers electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone. This protein is the largest subunit of complex I and it is a component of the iron-sulfur (IP) fragment of the enzyme. It may form part of the active site crevice where NADH is oxidized. Mutations in this gene are associated with complex I deficiency. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jan 2011]