Now, when scientists were basically studying this molecule, how exactly did they actually discover where the active side is found within this molecule? Well, instead of actually using the substrate molecules for this enzyme, they used an inhibitor, an irreversible inhibitor to this enzyme. They synthesized an irreversible inhibitor that resembles the two substrate molecules of this particular enzyme. So remember what Atcase actually does. It catalyzes the conversion of a molecule called aspartate and a second molecule called carbomol phosphate. So it combines these two molecules to form the end carbomol aspartate as well as a single orthophosphate molecule.