What types of enzymes play a catalytic role in the regulation pathway of ubiquitination?

ubiquitin activating enzyme ( E1), a ubiquitin conjugating enzyme (E2), and a ubiquitin ligase (E3).

Explanation:

In ubiquitination, ubiquitin (regulatory protein) attach to a protein to inactivate it and targets a protein for degradation via the proteasome.

There are three enzymes sequentially catalyse the process of ubiquitination that includes ubiquitin activating enzyme ( E1), a ubiquitin conjugating enzyme (E2), and a ubiquitin ligase (E3).

The E1 activates ubiquitin by forming a thiol ester bond between the C terminus of ubiquitin and the active cysteine of the E1 which is an ATP dependent step.

The activated ubiquitin then tranferred to cysteine of E2 which along with E3 transfers the ubiquitin to a lysine residue in the target protein.

Hence, all three ubiquitin activating enzyme ( E1), a ubiquitin conjugating enzyme (E2), and a ubiquitin ligase (E3) enzymes sequentially catalyse the process of ubiquitination.