Each subunit has an active site where the ligands are held. The crystallized structure of ACS was determined with CoA and Adenosine- 5′-propylphosphate bound to the enzyme.
Each subunit of ACS has an active site for binding ligands, similar to how other enzymes function. The crystallized form of ACS was studied with CoA and Adenosine-5′-propylphosphate attached to it.