Interaction between phosphofructokinase and aldolase from Saccharomyces cerevisiae studied by aqueous two-phase partitioning

Phosphofructokinase (EC 2.7.1.11) and aldolase (EC 4.1.2.13) have been highly purified from Saccharomyces cerevisiae by improved protocols. Partitioning of the enzymes in aqueous polymer two-phase systems was used to detect complex formation. The partition of each enzyme was found to be affected by the presence of the other enzyme. AMP affected the partition of the individual enzymes as well as the mixture of the two. The activities of the respective enzymes were stimulated in the putative complex in an AMP-dependent manner. Two strictly conserved residues belonging to an acidic surface loop of class II aldolases, are a potential site for electrostatic interaction with the positively charged regions close to the active site in phosphofructokinase.