Question

draw out step by step!! and have mini-explanations under each step explaining what is happnening

SHOW THE peptide bond hydrolysis mechanism of how:

a)cysteine proteases work

b) aspartyl proteases work

c) metallo proteases work

d)how does eptide hydrolysis by trypsin, elastase work with proteases?

Answer 1

1. Cysteine protease-

Cysteine proteases share a common catalytic mechanism involving a nucleophilic cysteine thiol in a catalytic triad that catalyzes the hydrolysis of peptide bonds using a deprotonated thiol moiety. A new thioester intermediate linking the carboxy-terminus of the substrate to the cysteine thiol is formed.

2. aspartyl proteases work-

Aspartyl proteases are a highly specific family of proteases – they tend to cleave dipeptide bonds that have hydrophobic residues as well as a beta-methylene group. Unlike serine or cysteine proteases these proteases do not form a covalent intermediate during cleavage. Proteolysis, therefore, occurs in a single step.

3.  metalloproteases activate a water molecule which performs a nucleophilic attack on the peptide bond to hydrolyse it.

4. In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides. The peptide products are then further hydrolyzed into amino acids via other proteases, rendering them available for absorption into the bloodstream. elastase cleaves at the peptide bond after amino acids with small side chains. Elastase cleaves the peptide bonds in elastin, aiding in the digestibility of this elastic protein