So once again, once citrate is formed in step one of the citric acid cycle, it must be transformed into its isomeric form, isocitrate. And this reaction, we basically transfer a hydroxyl group from the third carbon onto the adjacent carbon shown here. And what this process does, once again, is it prepares the molecule for a decarboxylation reaction that we'll talk about in the next step. Now, the enzyme that catalyzes this step is known as a connotase. And this aconitase actually contains an iron sulfur component. And that's why this molecule, the connotase enzyme, is known as an iron sulfur enzyme.