Metabolite Concentrations and Phase Relations in d‐Fructose Induced Glycolytic Oscillations

Abstract

AbstractThe frequency of glycolytic oscillations in yeast cells is only slightly modified by the consumption rate of either glucose or fructose, but it is reduced to 1 /2 to 2/3 if the ketohexose is the only substrate.Phase relations between NADH, adenine nucleotides and sugar phosphates (G‐6‐P, F‐6‐P, FDP, DAP) are independent of the hexose fermented.With fructose as a substrate the amplitudes of adenylates and hexose phosphates are distinctly smaller than with glucose. The maximum of G‐6‐P is higher with glucose and the minimum concentration of FDP is higher with fructose.In the transition to anaerobiosis FDP, adenosine 5′‐diphosphate and adenosine 5′‐phosphate are extremely high, whereas G‐6‐P, F‐6‐P and ATP concentrations are lower if fructose is the substrate fermented.The results are indicative for different control characteristics of the phosphofructokinase step, but on their basis it cannot be distinguished between a direct interaction of fructose (or one of its derivatives) on the phosphofructokinase kinetics or the existence of a bypass for fructose which might be able to withdraw a part of the substrate from the control point at the phosphofructokinase.