Question

Arrange the steps of the mechanism of chymotrypsin catalysis in order from first to last. Note that textbooks may not break out each of these steps individually, but all steps should be utilized.

His 57 ring N deprotonates Ser 195 hydroxyl
His 57 donates H to Ser 195 O, tetrahedral intermediate collapses
nucleophilic Ser 195 O- attacks carbonyl C of substrate
the C-terminal piece of peptide substrate (with new amino terminus) diffuses away
water donates H to ring N of His 57
hydroxide ion attacks carbonyl of remaining N-terminal piece of substrate
His 57 donates H to N of scissile peptide bond, tetrahedral intermediate collapses
N-terminal piece of peptide substrate (with new carboxyl terminus) diffuses away

Answer 1

The steps of the mechanism of chymotrypsin catalysis are arranged in order from first to last.

Step-by-step explanation:

The steps of the mechanism of chymotrypsin catalysis, arranged in order from first to last, are as follows:

1. Nucleophilic Ser 195 O- attacks the carbonyl C of the substrate.
2. His 57 donates H to N of the scissile peptide bond, tetrahedral intermediate collapses.
3. His 57 ring N deprotonates Ser 195 hydroxyl.
4. His 57 donates H to Ser 195 O, tetrahedral intermediate collapses.
5. Water donates H to ring N of His 57.
6. Hydroxide ion attacks the carbonyl of the remaining N-terminal piece of substrate.
7. The C-terminal piece of the peptide substrate (with new amino terminus) diffuses away.
8. The N-terminal piece of the peptide substrate (with new carboxyl terminus) diffuses away.

Each step plays a crucial role in the overall catalytic process of chymotrypsin, leading to the breaking down of peptide bonds and the formation of new peptide products.