So when the enzyme substrate complex forms over here, you can see that the substrate fits into the active site like a perfect puzzle piece like fit. The active site of the enzyme takes on a shape that is perfectly complementary to the shape of the substrate. And so if we take a look at our example down below of the lock and key model, notice that our enzyme is in purple here, and our substrate is this key shape here and so in the lock and key model, the substrate acts as the key, and the enzyme acts as the lock. And so what this means is that in the lock and key model, the shape of the active site is perfectly suited to the shape of the substrate to create a perfect puzzle piece like fit. And so, with the lock and key model, the shape of the active site on the enzyme is rigid and perfectly complementary to the substrates shape. But in our next lesson video, we'll talk about the induced fit model. And so in this video, we're on Lee going to talk about the lock and key model. And so the first main model is the lock and key model, whereas the second main model is the induced fit model. So it turns out that there are two main models for enzyme substrate, specificity or two main models for how the enzyme interacts with the substrate toe form the enzyme substrate complex. In this video, we're going to begin our discussion on the lock and key and the induced fit models.

Model lock and key