Question

question where does atp bind to phosphofructokinase? answer at a regulatory site, as an allosteric activator at the active site, as a substrate at the active site, as an allosteric regulator at both the active site and the regulatory site, as a substrate and an activator, respectively i dont know yet

Explanation:

Phosphofructokinase is an enzyme in glycolysis. ATP has dual roles with this enzyme. As a substrate, it binds at the active site for the phosphorylation reaction (converting fructose - 6 - phosphate to fructose - 1,6 - bisphosphate). As an allosteric inhibitor (not activator in high concentrations), it can also bind at a regulatory site. But looking at the options, the correct description of its binding sites considering its substrate role (active site) and its role as an allosteric regulator (though usually inhibitor, the option structure here - the fact that it can bind at both sites) is the key.

Answer:

At both the active site and the regulatory site, as a substrate and an activator, respectively.