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An amino acid, C6H13N3O3, originally isolated from watermelon, that is produced as an intermediate in the conversion of ornithine to arginine during urea formation in the liver.

[New Latin Citrullus, watermelon genus (from Medieval Latin citrullus, watermelon, from Italian dialectal citrulo, from Late Latin citrium, from Latin citrus, citron) + -ine.]


(Biochemistry) an amino acid that occurs in watermelons and is an intermediate in the formation of urea. Formula: NH2CONH(CH2)3CHNH2COOH
[C20: from Medieval Latin citrullus a kind of watermelon, from Latin citron, referring to its colour]


(ˈsɪ trəˌlin)

an amino acid, C6H13N3O3, abundant in watermelons and an intermediate compound in the urea cycle.
[1930; < New Latin Citrull(us) the watermelon genus (ultimately derivative of Latin citrus citrus)]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.citrulline - an amino acid that does not occur in proteins but is an intermediate in the conversion of ornithine to arginine
amino acid, aminoalkanoic acid - organic compounds containing an amino group and a carboxylic acid group; "proteins are composed of various proportions of about 20 common amino acids"
References in periodicals archive ?
Clinically proven ingredients like pterostilbene and citrulline work together to ward off both the external and internal mechanisms that damage cells and accelerate aging.
Ac anti-peptide cyclique citrulline (CCP) et Polyarthrite rhumatoide.
She had a plasma citrulline of 20 nmol/mL (reference range, 30-45 nmol/mL) and a urine orotic acid level of 1.
The non-GMO effervescent supplement includes Creatine MagnaPower, Sustamine, Citrulline Malate, SOD, Superfruit AuroraBlue blueberry, electrolytes, antioxidants, vitamins C, D, B6 and B12, and a host of Albion minerals.
Combine that with the continued research into the Citrulline in watermelon, which is shown to reduce blood pressure, and why would retailers not want their consumers to eat more watermelon?
Previous studies have found citrulline supplementation to be associated with smooth muscle relaxation, enhanced anaerobic athletic performance, relieved muscle soreness and accelerated lactic acid removal.
5 mg/L); erythrocyte sedimentation rate (ESR)=52 mm/h; rheumatoid factor (RF): 60 IU/mL (N: 0-14 IU/mL); positive anti-cyclic citrulline peptide (anti-CCP); and negative anti-nuclear antibody (ANA), HLA-B27, brucella agglutination, and HBsAg.
gingivalis to convert the amino acid arginine to citrulline.
NO is an inorganic free radical formed as a byproduct of the stepwise conversion of L-arginine to citrulline by hydroxylation.
Arginine is a conditionally essential amino acid as it can be obtained from the diet and is synthesised endogenously from the amino acid citrulline and sourced from the breakdown of proteins in the body.
Watermelon is also a natural source of citrulline, a non-essential amino acid with various health and athletic performance benefits.
Watermelons are also high in citrulline, an amino acid which, "improves the cardiovascular and immune system and thus has beneficial effects on the health of the blood vessels," she says.