||"The ratio between the oxidized and reduced forms of nicotinamide adenine dinucleotide ([NAD+]/[NADH]) is an important component of the cellular redox state. In KO [knockout] cells, this ratio was ~2-fold lower (i.e. more reduced) than in wt cells (Fig. 4C). In contrast, the ratio between [NADP+] and [NADPH] was not affected in KO cells. These findings suggest that CI- [complex I or NADH:ubiquinone oxidoreductase-] mediated NADH oxidation in KO cells is less efficient than in wt cells, inducing a reduction in [NAD+]/[NADH] ratio."