And then carbon two grabs that same HOA from that oxygen of this catalytic residue. And so, in the final step, we basically form this molecule, the aldos, our gap. And we also reform these two catalytic residues of the enzyme because, remember, enzymes are never actually used up at the end. They have to be regenerated. And so, ultimately, this is the process by which this catalysis reaction actually takes place. Now, there are two important things that this enzyme, trio phosphate isomerase, actually does.