Protease Mechanisms 2

The video tutorial explains the mechanism of caspases, enzymes that induce apoptosis by targeting specific peptide bonds. It details the formation of tetrahedral intermediates and the steps involved in the caspase reaction, including the role of histidine and proton exchanges. The tutorial also compares cysteine and serine proteases, highlighting their similarities and differences in mechanisms.

What is the primary role of caspases in cellular processes?

• Repairing DNA damage

• Inducing cell division

• Facilitating protein synthesis

• Inducing apoptosis

Which bond do caspases specifically target in proteins?

• Disulfide bond

• C-terminal peptide bond

• Phosphodiester bond

• N-terminal peptide bond

What is the first step in the caspase mechanism?

• Formation of a disulfide bond

• Deprotonation of cysteine

• Hydrolysis of ATP

• Protonation of histidine

What is generated after the nucleophilic attack on the carbonyl carbon in the caspase mechanism?

• A linear intermediate

• A cyclic intermediate

• A planar intermediate

• A tetrahedral intermediate

What role does histidine play in the caspase mechanism?

• It forms a covalent bond with the substrate

• It acts as a nucleophile

• It stabilizes the tetrahedral intermediate

• It regenerates its resting state by transferring protons

What is the main difference between cysteine and serine protease mechanisms?

• The type of bond targeted

• The number of intermediates formed

• The atom involved in the nucleophilic attack

• The type of leaving group

In the context of protease mechanisms, what is the first leaving group typically?

• A carboxylate ion

• An amine

• A water molecule

• A phosphate group