Final answer:
ATP synthase has three catalytic sites associated with its β subunits in the F1 portion of the enzyme, which are directly involved in the synthesis of ATP.
Step-by-step explanation:
ATP synthase possesses multiple catalytic sites for the synthesis of ATP. Specifically, the F1 portion of ATP synthase consists of six alternately arranged subunits: three α and three β, forming an arrangement known as F1(αβ)3. It is the β subunits within this complex that have catalytic activity and are responsible for the synthesis of ATP. During the process of ATP synthesis, the rotation of subunit F1γ causes conformational changes in the F1β subunits, which in turn facilitate the catalysis of ATP from ADP and inorganic phosphate.
The Fo portion of ATP synthase is a rotary mechanism embedded in the membrane, comprising several subunits including six c subunits that form a ring. Protons flow through channels between these c subunits, which results in rotational energy that drives the conformational changes in the F1(αβ)3 complex. However, it is important to note that while the entire ATP synthase complex is involved in the production of ATP, the actual number of catalytic sites corresponds to the number of β subunits, which is three.