Definition of ornithine in English:

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Pronunciation: /ˈɔːnɪθiːn/


[mass noun] Biochemistry
An amino acid which is produced by the body and is important in protein metabolism.
  • Chemical formula: NH2(CH2)3CH(NH2)COOH.
Example sentences
  • About 50-percent of ingested arginine is rapidly converted in the body to ornithine, primarily by the enzyme arginase.
  • When your body doesn't digest protein completely, gut bacteria convert two of the amino acids in protein, arginine and ornithine, to compounds called polyamines.
  • This may occur in part as a result of pathologically elevated activity of arginase, an enzyme that hydrolyzes arginine to ornithine and urea.


Late 19th century: from ornitho- (with reference to a constituent found in bird excrement) + -ine4.

For editors and proofreaders

Line breaks: or¦ni|thine

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