Now this process of Ubiquitination actually involves three different enzymes and three different processes. So enzyme number one, or step number one, basically utilize the enzyme we called Ubiquitin activating enzyme. And what this enzyme ultimately does is it harvests the energy that is released when we hydrolyze ATP and utilize that energy to actually activate that Ubiquitin molecule. And that prepares the ubiquitin It gives it enough energy to actually attach it ultimately onto that target protein. So the first step is catalyzed by Ubiquitin activating enzyme or E one. And this is catalyzed via the hydrolysis of ATP and the carboxyl.