So in this lecture, I'd like to focus on the cooperative nature of atcase and then discuss two allosteric effectors to this enzyme. So we're going to focus on citadine triphosphate CTP and adenosine triphosphate state ATP. Now, let's begin by discussing the quotinary structure of this enzyme and how its coronary structure actually affects the likelihood that the substrate will bind onto the active signs. Now, when the concentration of the substrate molecule is low inside the cell, the entire coordinary structure of the enzyme exists predominantly in the T state, the ten state. So what do we mean by the ten states? Well, in the ten state of this enzyme, the two catalytic primers and these are the orange structures in this diagram are basically found in close proximity with respect to one another, and they create a very compact and very constrained structure.