文摘
The fluorescent sensor Peredox was utilized for the first time to measure the [NADH]:[NAD+] ratio in a bacterial organism, Ralstonia eutropha. The Peredox sensor operates close to its saturation level in aerobically grown R. eutropha cells indicating a high [NADH]:[NAD+] ratio. Comparing Peredox signals in vivo and in R. eutropha lysates, we estimate the free cytosolic [NADH] as 28 µM and [NAD+] as 1.9 mM. Spectrally resolved fluorescence lifetime analysis provides a novel, sensitive tool for determining the [NADH]:[NAD+] using Peredox.