So let's take a look at the following diagram to see exactly what we mean. So, we have our Ubiquitin in its nonactive form. So in step one, we take an ATP molecule and we essentially transfer an amp from the ATP onto the Ubiquitin and we release a Pyrophosphate. So we see that the product of this particular reaction is an active ubiquitous molecule that contains this amp group. And so now it's a high energy molecule. We release the Pyrophosphate and now E One, this enzyme, the Ubiquitan activating enzyme, basically catalyze the transfer of this blue region onto the active side of E One.