Q3: Example of a question that requires understanding of the mechanism of chymotrypsin Below is a simplified schematic of one step in the reaction mechanism of chymotrypsin. Chymotrypsin Ser195) Ser195 B: , BH 2 0 1 C 3 -R 0 R! R2_N | H II 0 R? A) In this step, the residue indicated as "B" is playing the role of a base catalyst. Which residue is this? Why is this residue optimal for playing the role of base catalyst in this mechanism? B) The reaction step shown here has a transition state (known as the "tetrahedral intermediate"). The enzyme stabilizes this transition state in order to enhance the rate of the reaction. Briefly, describe how chymotrypsin stabilizes the tetrahedral intermediate