释义 |
xanthine
xan·thine X0001200 (zăn′thēn′, -thĭn)n.1. A yellowish-white, crystalline purine base, C5H4N4O2, that is a precursor of uric acid and is found in blood, urine, muscle tissue, and certain plants.2. Any of several derivatives of this compound.xanthine (ˈzænθiːn; -θaɪn) n1. (Elements & Compounds) a crystalline compound related in structure to uric acid and found in urine, blood, certain plants, and certain animal tissues. Formula: C5H4N4O22. (Elements & Compounds) any substituted derivative of xanthine, esp one of the three pharmacologically active methylated xanthines, caffeine, theophylline, or theobromine, which act as stimulants and diureticsxan•thine (ˈzæn θin, -θɪn) n. 1. a crystalline, nitrogenous compound, C5H4N4O2, related to uric acid, occurring in urine, blood, and certain animal and vegetable tissues. 2. any derivative of this compound. [1855–60; < French; see xantho-, -ine2] ThesaurusNoun | 1. | xanthine - crystalline oxidation product of the metabolism of nucleoproteins; precursor of uric acid; found in many organs and in urineorganic compound - any compound of carbon and another element or a radical | TranslationsXanthine
xanthine[′zan‚thēn] (organic chemistry) C5H4N4O2 A toxic yellow-white purine base that is found in blood and urine, and occasionally in plants; it is a powder, insoluble in water and acids, soluble in caustic soda; sublimes when heated; used in medicine and as a chemical intermediate. Also known as dioxopurine. Xanthine (2,6-dioxopurine) an intermediate product of the metabolic degradation of purine bases. Its structural formula is Xanthine forms yellow crystals. Its melting point is 220°C (with decomposition), and its molecular weight is 152.12. Xanthine dissolves poorly in water and better in alcohol. It displays the properties of a weak acid and a weak base. Widely found in nature (in small amounts), it is formed during the hydrolytic deamination of guanine or as a result of the aerobic oxidation of hypoxanthine in the presence of the enzyme xanthine oxidase. This enzyme also oxidizes xanthine to the final product of purine metabolism in man—uric acid—and this serves as a basis for xanthine determination. When this stage of xanthine metabolism is disrupted, xanthine accumulates in the body, primarily in the form of calcium salts (urinary calculus). xanthine
xanthine [zan´thēn] a purine compound found in most bodily tissues and fluids; it is a precursor of uric acid. Methylated xanthine compounds such as caffeine, theobromine, and theophylline are used for their bronchodilator effects.xan·thine (Xan), (zan'thēn), Oxidation product of guanine and hypoxanthine, precursor of uric acid; occurs in many organs and in the urine, occasionally forming urinary calculi; elevated in molybdenum cofactor deficiency and in xanthinuria.xanthine (zăn′thēn′, -thĭn)n.1. A yellowish-white, crystalline purine base, C5H4N4O2, that is a precursor of uric acid and is found in blood, urine, muscle tissue, and certain plants.2. Any of several derivatives of this compound.xan·thine (zan'thēn) Oxidation product of guanine and hypoxanthine, precursor of uric acid; occurs in many organs and in the urine, occasionally forming urinary calculi. See XAN See XANxanthine Related to xanthine: Xanthine oxidase, Xanthine DeHydrogenase, xanthine oxidase deficiencyWords related to xanthinenoun crystalline oxidation product of the metabolism of nucleoproteinsRelated Words |