substrate molecules. And so ultimately, as more of the active sites become filled with those substrate molecules, the equilibrium basically shifts to the r state. And what that means is at a high concentration of substrate, when most of the active sites will be filled by the substrate molecule, all the enzymes will exist predominantly in the r state. But in the absence of the substrate molecule, when none of the active sites are filled by the substrate molecules, that means all the enzymes will predominate in the T state. Now, the thing about the Rstate is the r state describes this relaxed state, relaxed structure where there is not too much constraint and so definitive of the active side for the substrate is high and that represents a high catalytic activity, a high catalytic rate. Now, what we still haven't discussed is where the CTP actually binds to and how exactly does the binding of the CTP molecule to the regulatory dimer?