So we have this triangular form as shown in this diagram. Now, the question is, what exactly is the interaction like between regulatory dimers and these catalytic triumphs? Well, it turns out that each one of the regulatory chains in each one of these dimers interacts with one of these catalytic chains in each one of these catalytic trimmers. And this interaction is made better. It is amplified by the presence of a metal atom, of a zinc metal atom. So if we examine so let's take a look at one of these red structures.