| anhydrase | <enzyme> An enzyme that catalyses the removal of water from a compound; most such enzymes are now known as hydrases, hydro-lyases, or dehydratases. Carbonic anhydrase, a zinc-containing enzyme that catalyses the interconversion of CO2 with HCO3- and H+. There are at least seven human isozymes that appear predominantly in red blood cells, secretory tissues, muscle, etc. A deficiency of carbonic anhydrase II can result in osteopetrosis and metabolic acidosis. The inhibition of carbonic anhydrase IV and possibly carbonic anhydrase II by sulfonamides is a current therapy in the treatment of glaucoma. Synonym: carbonate dehydratase, carbonate hydro-lyase. (05 Mar 2000) |
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| anhydration | The condition that results from excessive loss of body water. Synonym: anhydration, deaquation, hypohydration. Origin: L. De = away, Gr. Hydor = water (18 Nov 1997) |
| anhydride | <chemistry> A compound that becomes an acid in the presence of water or becomes a base when water is removed. (12 Nov 1997) |
| anhydrides | Chemical compounds derived from a substance, especially an acid, by the abstraction of a molecule of water. The anhydrides of bases are oxides; those of alcohols are ethers. (12 Dec 1998) |
| anhydrite | <chemical> A mineral of a white a slightly bluish colour, usually massive. It is anhydrous sulphate of lime, and differs from gypsum in not containing water (whence the name). See: Anhydrous. Source: Websters Dictionary (01 Mar 1998) |
| anhydro- | Chemical prefix denoting the removal of water. Compare: pyro-. Origin: G. An-priv., + hydor, water (05 Mar 2000) |
| anhydroelastase | <chemical> Catalytically inert derivative of elastase in which the active-site residue ser-195 has been converted to a dehydroalanine residue (26 Jun 1999) |
| anhydrogitalin | C41H64O14;a secondary cardiac glycoside from Digitalis purpurea and D. Lanata. Synonym: anhydrogitalin, bigitalin, pseudodigitoxin. (05 Mar 2000) |
| anhydroleucovorin | An intermediate formed in the folic acid-catalyzed glycine-serine interconversion. Synonym: N5,N10-methenyltetrahydrofolic acid. (05 Mar 2000) |
| anhydrosugars | Sugars from which one or more molecules of water, other than water of crystallization, have been eliminated. Synonym: dehydrosugars. (05 Mar 2000) |
| anhydrotetracycline oxygenase | <enzyme> Streptomyces aureofaciens enzyme catalyzing penultimate reaction of tetracycline biosynthesis, hydration of anhydrotetracycline to dehydrotetracycline Registry number: EC 1.14.99.- (26 Jun 1999) |
| anhydrous | <chemistry> A substance deprived or destitute of water. (12 Nov 1997) |
| anhydrous alcohol | Water having been removed. Synonym: anhydrous alcohol. (05 Mar 2000) |
| anhydrous chloral | CCl3-CHO; trichloroacetaldehyde;a thin oily liquid with a pungent odour, formed by the action of chlorine gas on alcohol. Synonym: anhydrous chloral. (05 Mar 2000) |
| anhydrous lanolin | Lanolin that contains not more than 0.25% of water; used as a water-adsorbable ointment base. (05 Mar 2000) |