So, step number one is catalyzed by pyruvate dehydrogenase and it contains a prosthetic group we call Thyamine, pyrophosphate TPP. And this enzyme, the E one enzyme of this pyruvate dehydrogenate complex, uses this prosthetic group to actually attach onto that pyruvate molecule and at the same time remove a carbon dioxide. Now, this step is not actually a single step. It contains individual steps. But I didn't have space to basically draw the steps out. So this is what happens.