Figure 1.

(a) Fluorescence of NAD(P)H in a stirred suspension of yeast cells with respect to time (s). As fluorescence signals are recorded in an arbitrary unit, it is not shown. The first steep rise of fluorescence signal is caused by the addition of glucose at 50 s and the second sharp change by the addition of cyanide at 230 s, yielding initial concentrations of 24 mM and 5 mM, respectively. (b) Concentration of NAD(P)H in a closed system obtained from the model in a previous study (1) by removing the flow and setting the initial concentration of extracellular glucose to 24 mM.