The regulatory properties of yeast pyruvate kinase. Effect of fructose 1,6-bisphosphate

Abstract

The kinetics of pyruvate kinase from Saccharomyces cerevisiae were studied in assays at pH 6.2 at 25 degrees C as a function of the concentrations of the substrates ADP, phosphoenolpyruvate and Mg2+ and the concentration of the effector fructose 1,6-bisphosphate. The enzyme was activated by 100 mM-K+ and 32 mM-NH4+ throughout. It was found that an increase in the fructose bisphosphate concentration from 24 microM to 1.2 mM brings about a transition from a sigmoidal to a non-inflected form in the relationships v = f([phosphoenolpyruvate]) and v = f([Mg2+]) together with a large increase in the affinity of these substrates for the enzyme. The binding behaviour of ADP is barely affected by the same change in effector concentration. By contrast, increase in fructose bisphosphate concentration below 24 microM increases the affinity of the enzyme for all its substrates and the sigmoidicity of the corresponding velocity-substrate-concentration relationships. As a result of this change in behaviour it has been found impossible to represent all the data by the exponential model for a regulatory enzyme, and it is suggested (supported by comparisons with previous work) that the failure may reflect a secondary action of the effector upon the enzyme.

Quantitative Analysis of the High Temperature-induced Glycolytic Flux Increase in Saccharomyces cerevisiae Reveals Dominant Metabolic Regulation

“…We propose additionally that a high flux can be maintained in the absence of a pyruvate sink by the feedback activation of PFK driven by the increased level of fructose 2,6-bisphosphate (65), and a feed-forward activation of pyruvate kinase by the increased level of fructose 1,6-biphosphate (66,67). This last aspect is complicated by the fact that such regulatory effects themselves may be temperature-dependent.…”

Mutation Arg336 to Lys in Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase originates an enzyme with increased oxaloacetate decarboxylase activity

“…The possibility of contamination of S. cerevisiae PEP carboxykinases with S. cerevisiae PK can be discarded because the PK‐like activities of the wild type and mutant carboxykinases show hyperbolic kinetics for PEP and lack of activation by fructose 1,6‐bisphosphate (data not shown). S. cerevisiae PK displays cooperative behavior against PEP saturation and is activated by fructose 1,6‐bisphosphate [3,13,14].…”

Brewing yeast genomes and genome‐wide expression and proteome profiling during fermentation

“…The analysis of genes encoding proteins involved in pyruvate metabolism suggests that significant upregulation occurs, particularly for PYC1 and PDH 225. Perhaps this is not surprising, since pyruvate is central to both the TCA cycle and alcoholic fermentation190.…”