Put the steps of the mechanism of chymotrypsin catalysis in order from first to last. note: your textbook may not break out each of these steps individually, but all steps should be utilized.

Question

Biology

Reina Villarreal

2 August, 20:10

Put the steps of the mechanism of chymotrypsin catalysis in order from first to last. note: your textbook may not break out each of these steps individually, but all steps should be utilized.

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Triston Harding · Answer 1

The steps are the following:

-His 57 catalyses removal of H from Ser 195 hydroxyl.

-Ser 195's nucleophilic O attacks carbonyl C of substrate.

-His 57 donates H to N of sissile peptide bond, tetrahedral intermediate decomposes.

-The portion (the C-terminal end) of original substrate with the new amino terminus diffuses away.

-Water donates H to His 57

-Resulting OH attacks carbonyl of ramining substrate

-His 57 donates H to Ser 195O, leading to collapse of tetrahedral intermediate

-The portion (N-terminal end) of original substrate with the new carboxylate terminus diffuses away.

Explanation:

It can be said that the primary structure of the compound called chymotrypsin is formed by disulfide bonds, in addition to the active site composed of Ser-195, His-57 and Asp-102. Ser-195 is linked to His-57 via a hydrogen bond and to Asp-102 via a hydrogen bond. The function of His-57 is to polarize the hydroxyl group, while Asp-102 targets His-57 and stabilizes it through hydrogen and electrostatic bonds.