And in the first step of this process, we essentially use an ATP molecule to activate the carbon dioxide to form the carboxy phosphate. This is our carboxy phosphate complex. And so we form the ATP that we have here on the product side. So now that we have an active CO2 molecule, it is ready to be attached onto the biotin component of that enzyme. And that's exactly what happens in step two. Now, I should mention that there is a requirement to attach that CO2 onto the biotin.