Chaotic dynamics in yeast glycolysis under periodic substrate input flux.

The numerical analysis for a glycolytic model containing the enzymes phosphofructokinase and pyruvate kinase reveals different types of entrainment, as well as chaotic response under sinusoidal substrate input. Entrainment with response periods 1, 2, 3, 5 and 7-times the input flux period and aperiodic behaviour is verified by measurements of NADH fluorescence in extracts of Saccharomyces cerevisiae in the theoretically predicted range. The stroboscopic transfer function obtained from the aperiodic signal admits period 3, implying chaos according to the Li-Yorke theorem.