And once we create this covalent modification, the Irreversible inhibitor basically blocks the activity of that enzyme. And so we know that because the activity of the enzyme is inhibited, that means that the DIPF must be bound to a Serene found inside the active site. Now, out of all the 28 Serene amino acids that we find in China Trypsin, this is the only serine that reacts with DIPF. And this is found inside the active side. And so that implies that it's this Serene molecule. And the serine molecule has a number of 195.