Question

Why does the hydrolysis of peptide bonds by the proteasome get decreased when the domain of ATPase is inhibited?

Answer 1

The 20S proteasome is a large multicomponent protease complex. It is ATP dependent, If the ATPase is inhibited then the proteasome activity of hydrolysis of peptide bond gets decreased because proteasome needed proper amount of energy in the form of ATP i.e. Adenosine triphosphate. Meanwhile proteasome function gets distorted.

ATPases are a group of enzymes that catalyze the hydrolysis of a phosphate bond in adenosine triphosphate (ATP) to form adenosine diphosphate (ADP). They harness the energy released from the breakdown of the phosphate bond and utilize it to perform other cellular reactions.

Most intracellular proteins, both short and long lived, are degraded by the ATP-dependent proteolytic complex known as the 26 S proteasome (1). This structure generates diverse peptides, most of which range in length from 2 to 24 residues. The intracellular peptidases that hydrolyze the large variety of peptides released by proteasome.

The degradation of ubiquitinated proteins by 26 S proteasomes requires ATP hydrolysis. Protein breakdown in eukaryotic cells requires ATP consumption at multiple steps. Proteins are targeted for degradation through the ATP-dependent addition of a ubiquitin chain, which leads to their ATP-dependent binding and proteolysis by the 26 S proteasome.