And what happens is this Serene molecule, the oxygen, basically binds onto this carbon and that kicks off this first dalanine to basically form the astle intermediate as well as this individual D. Alanine that was removed. And now what happened is we basically prepare this section here. So this molecule here to form that cross linkage between this carbon here and this nitrogen here. So in the next step, this pensaclyne would basically move into the active side and the enzyme would catalyze the formation of that cross linkage between this nitrogen here and this carbon here. So this is how that catalyzation process actually takes place normally in the absence of penicillin. Now, what happens when we add penicillin?