Now, before we add any polymolecules, when they are not present in the environment, in the absence of the polysubstrate or the actual substrate, the aspartate or the carbo moyl phosphate, the coronary structure exists in the T state. And in this state, the enzyme has a low affinity for the subtract molecules and will display a low catalytic activity. On the other hand, as we begin to add the polymer molecules, they begin to slowly add into the active sides found in those catalytic primers. And as they begin to fill those active sides, what that does is it moves. So this is one trimer. This is a second trimer.