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xanthine

Line breaks: xan|thine
Pronunciation: /ˈzanθiːn
 
/

Definition of xanthine in English:

noun

[mass noun] Biochemistry
1A crystalline compound found in blood and urine which is an intermediate in the metabolic breakdown of nucleic acids to uric acid.
Example sentences
  • Xanthine oxidase catalyses the oxidation of xanthine and hypoxanthine to uric acid and is a well-known producer of superoxide radicals.
  • It appears that the purine metabolic system in humans has found a way to avoid the overproduction of uric acid by downregulating the Xor gene expression, the product converting hypoxanthine to xanthine and further xanthine to uric acid.
  • Xanthine oxidase activity was evaluated by the spectrophotometric measurement of the formation of uric acid from xanthine.
1.1 [count noun] Any of the derivatives of this, including caffeine and related alkaloids.
Example sentences
  • Methyl xanthines (caffeine, theophylline and theobromine) are found in seeds and leaves of a variety of unrelated plant species, including coffee, tea, cocoa, cola and mate.
  • Ephedrine and the xanthines, such as caffeine and theophylline, increase metabolic rate.
  • The main components of this tea are natural xanthines such as caffeine, theobromine, theophylline and tanni.

Origin

mid 19th century: from xanthic + -ine4.

Definition of xanthine in:

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