What does anhydrase mean?
An anhydrase is an enzyme that accelerates chemical reactions involving the removal or addition of water. By far the most familiar member of this group is carbonic anhydrase, an exceptionally fast enzyme found in red blood cells, the kidneys, and the eye, where it interconverts carbon dioxide and water with bicarbonate and hydrogen ions. This single reaction underlies carbon dioxide transport in the blood, acid–base balance, and fluid regulation in tissues. Anhydrases matter far beyond basic physiology: drugs that inhibit carbonic anhydrase are used to treat glaucoma, certain seizures, and altitude sickness, and the enzyme is a staple of biochemistry teaching because it illustrates how catalysts achieve staggering speed — millions of reactions per second. The word itself derives from Greek roots meaning 'without water', joined to '-ase', the standard suffix for enzymes. Although largely a specialist term, anhydrase appears regularly in medical, pharmaceutical, and research contexts.
nounAn enzyme that catalyzes the removal of water from a compound, or the reverse reaction of hydration. The best-known example is carbonic anhydrase, which interconverts carbon dioxide and water with bicarbonate and protons.
- Any enzyme that catalyzes the removal of water from a substrate (dehydration) or its addition (hydration), most famously carbonic anhydrase in respiration and pH regulation.
"Carbonic anhydrase in red blood cells speeds up the conversion of carbon dioxide into bicarbonate by a factor of nearly a million."
"Carbonic anhydrase in red blood cells rapidly converts carbon dioxide into bicarbonate for transport to the lungs."
"Researchers screened a panel of compounds as potential anhydrase inhibitors for treating glaucoma."
Pluralizes regularly; used when discussing multiple members of this enzyme class.
"Several anhydrases have been characterized from thermophilic bacteria."
One molecule of carbonic anhydrase can hydrate over a million molecules of CO2 per second — making it one of the fastest enzymes known.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of anhydrase
The word combines the Greek-derived prefix 'an-' ('not') and 'hydor' ('water') — the same root behind 'anhydrous' and 'anhydride' — with the '-ase' suffix introduced around the turn of the twentieth century when enzymes began to be systematically named after the reactions they catalyze. It thus literally means a water-removing agent, coined once biochemists identified proteins that speed dehydration and hydration reactions.
Related word forms
How anhydrase is actually used
A technical term confined to biochemistry, physiology, and pharmacology; it is rarely encountered outside scientific writing. In modern enzymology the systematic name 'dehydratase' is often preferred, but 'anhydrase' remains standard for carbonic anhydrase, whose inhibitors are widely prescribed drugs (e.g., for glaucoma and altitude sickness).
Easily confused with anhydrase
'Anhydrous' describes a substance containing no water, while 'anhydrase' is an enzyme that catalyzes water removal.
The terms are closely related; 'anhydrase' is the broader traditional name for a water-removing enzyme, while 'dehydratase' is the systematic Enzyme Commission term used in modern biochemistry nomenclature.