So let's begin with diagram one. Now, if we go into the active side of this enzyme, we'll basically see a bunch of these alpha beta barrels. So we'll see these structures, and in the active side, there are basically two catalytic residues that catalyze this reaction and they catalyze via an acid base reaction. So we'll see exactly what that means in just a moment. So what are these two catalytic residues? Well, we have the glue 165 and the his 95.