Biochem chymotrypsin order

Substrate binds to the hydrophobic pocket.

___1___

Histidine acts as a general base to active a serine OH group.

___2___

A serine alkoxide ion attacks a carbonyl carbon of the substrate, forming a covalent acyl bond between enzyme and substrate.

__3___

A tetrahedral transition state involving an oxyanion is stabilized by the oxyanion hole.

__4,9__

Histidine acts as a general acid to protonate an amide nitrogen. The peptide bond is broken and the first product dissociates.

5_

Histidine acts a general base to convert water into a hydroxide ion.

__7___

Histidine acts as a general acid to protonate the serine oxygen group, breaking the acyl bond between enzyme and substrate. The second product dissociates.

__10__