Affixes

In chemical naming this indicates the loss of one or more hydrogen atoms, a process called dehydrogenation; examples include dehydrocholesterol, a derivative of cholesterol present in the skin that is converted to vitamin D by sunlight, and dehydroacetic acid, a cyclic compound derived from acetic acid that is sometimes used as a fungicide. A dehydrogenase is an enzyme that catalyses the removal of hydrogen atoms from a particular molecule, examples being glucose dehydrogenase, choline dehydrogenase, and alcohol dehydrogenase. To dehydrate, to lose water from the body, comes directly from Greek hudros, hudr‑, water.