It uses a twostep reaction to basically produce an important inflammatory molecule we call prostaglandin H Two. And what prostagland H Two does is it basically initiates the inflammation response. It basically stimulates that inflammation response that is carried out by our immune system, and it also acts, actually regulates the secretion of gastric acid by the gastric cells of Aristonic. So this is a two step process that it catalyzes. So the substrate molecule of this particular enzyme is the arachidonic acid. And the arachidonic acid exists in its deprotonated state.