Now, the question is, why is this true? So Trypsin uses the same exact catalytic triad that climate Trypsin uses. But what gives this Trypsin the difference in specificity? Well, if we examine the s one pocket of Trypsin at the bottom of that s one pocket, we're going to see a residue that we don't see in the s one pocket of Chimetrypsin at the bottom of the Trips. In s one pocket, we have a negatively charged side chain that came from the aspartate that we see in Trypsin and we don't see in Chimetrypsin. So as a result of the negatively charged side chain of Aspartade 189 that is found at the bottom of the s one Trypsin pocket, we see that this Trypsin only Cleaves at the carboxyl end of those amino acids which are long and contain a positive charge at the end.