And these are known as disulfide bridges or disulfide bonds. So it turns out that if we have 215 amino acids that are in close proximity, if an oxidation reaction takes place, we can form a covalent bond between our sulfur groups. So basically, an oxidation reaction takes place. We take away this H atom, this H atom. We take away two electrons, and we form the following single covalent bond between the two sulfurs. And this is known as a disulfide bond or a disulfide bridge.