ornithine

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ornithine

 [or´nĭ-thēn]
an amino acid obtained from arginine by splitting of urea; it is an intermediate in urea biosynthesis.
ornithine carbamoyltransferase (ornithine transcarbamylase) an enzyme that catalyzes a reaction occurring in the liver mitochondria as part of the urea cycle.

or·ni·thine (Orn),

(ōr'ni-thēn, -thin),
2,5-Diaminovaleric acid; the l-isomer is the amino acid formed when l-arginine is hydrolyzed by arginase; not a constituent of proteins, but an important intermediate in the urea cycle; elevated levels seen in certain defects of the urea cycle.

ornithine

/or·ni·thine/ (or´nĭ-thēn) an amino acid obtained from arginine by splitting of urea; it is an intermediate in urea biosynthesis.

ornithine

(ôr′nə-thēn′)
n.
An amino acid, C5H12N2O2, not found in proteins, formed by hydrolyzing arginine and important in the formation of urea.

ornithine

[ôr′nithēn]
an amino acid, not a constituent of proteins, that is produced as an important intermediate substance in the urea cycle. It is formed by the hydrolization of arginine by arginase and is subsequently converted into citrulline. It decomposes by losing carbon dioxide, producing putrescine and a strong foul odor characteristic of decaying animal tissue. Also called diaminovaleric acid.

or·ni·thine

(ōr'ni-thēn)
The amino acid formed when l-arginine is hydrolyzed by arginase; an important intermediate in the urea cycle; elevated levels seen in certain defects of the urea cycle.

ornithine

dietary supplement which in combination with other amino acids arginine and lysine is claimed to increase muscle growth/lean body mass to a greater extent than strength training alone, but this has not been supported by properly designed trials. See also ergogenic aids; appendix 4.4 .

or·ni·thine

(Orn) (ōr'ni-thēn)
Amino acid formed when l-arginine is hydrolyzed by arginase; important intermediate in the urea cycle.

ornithine (ôr´nəthēn´),

n an amino acid, not a constituent of proteins, that is produced as an important intermediate substance in the urea cycle.
ornithine carbamoyltransferase,
n an enzyme in the blood that increases in patients with liver and other diseases.

ornithine

an amino acid obtained from arginine by the action of the enzyme arginase which also splits off urea; it is an intermediate in urea biosynthesis.

ornithine carbamoyl transferase (OCT), ornithine transcarbamoylase
see ornithine carbamoyl transferase.
ornithine cycle
alternative name for urea cycle since ornithine is the carrier of the nitrogens.
ornithine decarboxylase test
a means of identifying different members of the Enterobacteriaceae as well as other gram-negative bacteria.
ornithine-δaminotransferase
deficiency see gyrate atrophy.
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