Final answer:
In Boyer's Binding Change Mechanism, the catalytic site with low affinity for nucleotides, allowing ATP release, is the one that changes conformation after ATP hydrolysis. This site's decreased affinity facilitates the dissociation of ATP, a crucial step in ATP synthase's function.
Step-by-step explanation:
In the context of Paul Boyer's Binding Change Mechanism concerning ATP synthase's activity, it is asserted that the enzyme's three catalytic sites exist in various conformations leading to differing affinities for nucleotides. Specifically, after ATP binds and causes myosin to release actin, ATP is converted to ADP and phosphate, and the site's conformation changes, which lowers its affinity for ATP, allowing ATP release. This is in line with allosteric modulation, where a molecule binding at one site can affect the binding properties at a different site, such as how an allosteric inhibitor might decrease the active site's affinity for its substrates, or allosteric activation, which would induce a conformational shift increasing the active site's affinity.
Therefore, the catalytic site that would have a low affinity for nucleotides, resulting in the release of ATP, is the one that has undergone a conformational change upon ATP hydrolysis. This shift imparts a lower affinity for ATP and a higher affinity for ADP and inorganic phosphate. The stage at which ATP is released is crucial for the ATP synthase machinery's proper function.