In this video, we're going to introduce Phosphorylation. Phosphorylation refers to the transfer of a phosphate group from ATP to another molecule in order to provide energy. Phosphorylation by ATP hydrolysis can actually have a wide variety of effects. Some of those effects include activating a target molecule so that it's capable of reacting, as well as changing the conformation of a target protein. Notice in the image on the left-hand side, we're showing a glucose molecule here as the green hexagon, and this glucose molecule is shown in its inactive form, so it's not able to react in this form. However, after ATP hydrolysis and phosphorylation of the glucose molecule, adenosine triphosphate, ATP, which has three phosphates, transfers the third phosphate to glucose. This phosphorylated form of glucose is actually the active form and would be able to go on to react.

Phosphorylation does not always lead to the activation of a target molecule. This is just an example of what phosphorylation can lead to, as it can have a wide variety of effects. In some scenarios, phosphorylation will lead to activation, but in other scenarios, it could lead to inactivation. The idea here is that phosphorylation can have a wide variety of effects. On the right-hand side, we focus on a protein represented by a red circle. Notice that after ATP hydrolysis and phosphorylation of the protein, the protein takes on a completely different conformation, changing its shape, structure, and likely its function as well. You can see the phosphorylated protein here has an altered conformation. This concludes our introduction to phosphorylation and how ATP is usually the source of the phosphate group in phosphorylation. Phosphorylation can lead to a wide variety of effects, including activating a target to react and changing the conformation of a target protein. This concludes our lesson, and I'll see you guys in our next video.