Modelling diauxic glycolytic oscillations in yeast

Glycolytic oscillations in a stirred suspension of starved yeast cells is an excellent model system for studying the dynamics of metabolic switching in living systems. In an open flow system the oscillations can be maintained indefinitely at a constant operating point where the oscillations can be characterised quantitatively by experimental quenching and bifurcation analysis. The open system behavior has been described successfully by a model for the primary fermentative reactions in yeast that quantitatively describes the oscillatory dynamics. This model, however, fails to describe the transient behaviour of metabolic switching in a batch experiment by feeding the yeast suspension with a glucose pulse ‐‐ notably the initial NADH spike and final NADH rise. Experimental and computational results strongly suggest a regulation of ACA to explain the observed behaviour. The original model have extended with a regulation of PDC, a reversible ADH, and a drainage of Pyr. By using the method of time rescaling in the extended model the description of the transient batch experiments have been significantly improved. The results demonstrate that easy‐setup batch experiments are useful for investigations of the dynamics of the central metabolism of yeast cells.