Mechanistic study on the role of the NAD+–NADH ratio in the glycolytic oscillation with a pyruvate sensor

A bioelectrochemical pyruvate sensor is applied to the monitoring of the glycolytic oscillation. This method allows acetaldehyde (or NADH) perturbation experiments. A moderate extent of acetaldehyde addition causes the phase reset of the oscillation of pyruvate as well as NADH. The phenomenon is reasonably explained by our model, whereby the NADH consumption catalyzed by alcohol dehydrogenase (ADH) activates glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transiently and then ADP is effectively phosphorylated by the succeeding 3-phosphoglycerate kinase (3-PKG) reaction, which decelerates the phosphofructokinase (PFK) reaction and then the glycolytic flux. The fast transmission of information from the increase in the NAD+–NADH ratio by acetaldehyde addition to the decrease in the ADP–ATP ratio was verified experimentally by a model enzyme system composed of ADH, GAPDH, and 3-PKG. The acetaldehyde-driven ADP removal in the ADH–GAPDH–3-PKG system is proposed to play an important role in the glycolytic oscillation. The significance of the NAD+–NADH ratio on the period of the glycolytic oscillation is also discussed.