00:01
Hello students, here the question is about the peptides.
00:03
So for peptides, we have to identify the mechanism of carboxypeptidase a.
00:09
So it is a zinc metal enzyme that leaves peptide bond at the c terminal, at end of the peptide chain.
00:14
First, substrate of peptide chain binds to the active site of carboxypeptidase a.
00:21
Substrate binds to the active site of carboxypeptidase a.
00:42
After that, activation of water molecule.
00:57
That the bound water molecule is activated by coordination with the zinc ion in the active site and this activation increases the nucleophilicity of the water molecule making it capable of attacking the carbonyl carbon of the peptide bond.
01:08
After that, it is a nucleophilic attack.
01:16
So, the activated water molecule acts as a nucleophile and attacks the carbonyl carbon of the peptide bond resulting in the formation of tetrahedral intermediate.
01:25
So, after that, protonation of the leaving group because the general acid typically a histogen residue donates the proton to the leaving group which is the amino terminus of the peptide chain and this protonation helps in the departure of leaving group and facilitates the breakdown of the tetrahedral intermediate...