Question

In the reaction mechanism of chymotrypsies, formation of the tetrahedral intermediate is then followed by the formation of an acyl enzyme Intermediate. What active site residue(s) /are responsible for forming the first intermediate , and what type of catalysis occurring the first step of the reaction ?

Answer 1

Two new inhibitors in which the terminal α-carboxyl groups of Z-Ala-Ala-Phe-COOH and Z-Ala-Pro-Phe-COOH have been replaced with a proton to give Z-Ala-Ala-Phe-H and Z-Ala-Pro-Phe-H, respectively, have been synthesized.

It is estimated that oxyanion stabilization and the increased effective molarity of the catalytic serine hydroxyl group can account for the catalytic efficiency of the reaction. substrate binding induces the formation of a strong hydrogen bond or low-barrier hydrogen bond between histidine-57 and aspartate-102 that increases the pK(a) of the active site histidine, allowing it to be an effective general base catalyst for the formation of the tetrahedral intermediate. Homogeneous catalysis occurs.