Well, as we discussed in our discussion on Irreversible inhibitors, we said that penicillin is an example of a suicide inhibitor. And what that basically means is what penicillin does is it moves into the active side of this enzyme, the glycopeptide transpeptidase, and it tricks the active side, the enzyme, it tricks it into thinking that the penicillin is actually a substrate. And so this enzyme is going to treat the penicillin as if it was a substrate. It's going to begin the catalyzation process. But as soon as it begins the catalyzation process, what happens is because of the reactive nature of the penicillin. So remember, from organic chemistry, whenever we have a structure, a ring that consists of four atoms, so four member ring that creates a lot of steric hindrance and that increases the energy of that ring, and it makes it very reactive.