Oxidation of the mitochondrial NADH pool decreases sensitivity to sulfide-mediated activation of glycolysis.A and B, glucose consumed in 20 min in 5% suspensions in modified PBS (DPBS) (w/v) of HT29 cells expressing an empty vector (A) or mito-LbNOX (B) at different concentrations of Na2S. ∗,∗∗ Indicate a statistically significant difference from the corresponding control (minus Na2S) with p < 0.03 and p < 0.003, respectively. #Indicates a statistically significant difference from the empty vector control, p < 0.003; ns is not significant. ˆIndicates a significant difference between the adjacent bars, p < 0.01. C and D, kinetics of sulfide disappearance (C) and thiosulfate formation (D) in DPBS alone or containing a 10% suspension (w/v) of HT29 cells expressing an empty vector or the cytoplasmic or mitochondrial forms of LbNOX as indicated. Data represent the mean ± SD of three experiments.