And that's because the active side and the oxyanion whole of this particular Zymogen is not yet formed. It's not in the proper confirmation to be able to actually fit this substrate molecule. So what has to happen is this Chimotrypcinogen has to actually be activated proteolytically. And we'll see how that happens in just a moment. First, let's actually discuss where the Chimotrypcinogen is formed. So if we study the pancreas of our body, in the pancreas, we're going to find these special cells, exercise cells known as acinor cells.