So at the end, we basically formed the following denatured enzyme, the enzyme that if not in its active form. Now, what he did next was by using a semipermeable membrane, he removed these two agents at the same exact time. So he isolated this denatured enzyme by removing these two agents at the same time. And eventually he saw what happened is because this denatured enzyme was in the presence of oxygen, the oxygen in the air was able to basically reform those disulfide bonds. So it oxidized those disulfide bonds, reform those disulfide bonds. And eventually, because the urea was also removed at the same time, the non covalent interactions also reformed.