| pubmed-article:161131 | pubmed:abstractText | Phosphofructokinase from baker's yeast (Saccharomyces cerevisiae) is an octameric enzyme which exhibits complex allosteric behaviour. In contrast to mammalian phosphofructokinase, the enzyme does not show association-dissociation behaviour. A systematic kinetic investigation at pH 7.2 in dependence on the substrates, fructose 6-phosphate and ATP as well as on the effectors AMP and ADP is presented. The results are interpreted in terms of a structure oriented theoretical model. Because the two state model of Monod, Wyman and Changeux proved to be insufficient for interpretation of the experimental data, it was extended to a four state model in which the basic conformations R and T of the enzyme are split into subconformations R1 and R2 as well as T1 and T2, respectively. It is assumed that fructose 6-phosphate and the adenine nucleotides influence different allosteric equilibria. The model permits a precise quantitative description of the experimental data. | lld:pubmed |
