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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 ?
The concentrations of three amino acids, namely arginine, citrulline and ornithine, were analysed from their fasting glucose samples, and this data was used to calculate their global arginine bioavailability ratio (GABR).
In a study, they said that watermelon contains a high concentration of citrulline, an amino acid that can improve blood flow to the penis without the side effects of Viagra.
Hypercitrullination refers to the excessive production of the amino acid citrulline through conversion of arginine to citrulline residues.
The results showed that aspartate, betaine, choline, cysteine, ethanol, and threonine were increased over 2-fold in the muscle; propionate and trimethylamine were increased over 2-fold in the plasma; and alanine, glycerol, inosine, lactate, and pyruvate were increased over 2-fold and acetoacetate, arginine, citrulline, creatine, glutamine, glutarate, hippurate, lysine, methionine, phenylacetylglycine, taurine, trigonelline, trimethylamine, and trimethylamine N-oxide were decreased below 0.
WATERMELON TO BOOST LIBIDO "Watermelon is packed with the phytonutrient citrulline which increases the body's level of nitric oxide," said Shona.
The ester can be formed from various substances derived from food and beverages, including hydrogen cyanide, urea, citrulline, and other N-carbamyl compounds.
Kristi White and Amy Ellis, researchers in the College of Human Environmental Sciences, believe that several natural ingredients in watermelon--lycopene, citrulline, arginine, glutamine, and ascorbic acid --will act in synergy to decrease arterial stiffness and oxidative stress.
According to the company, PRX-ASL has shown therapeutic potential in a preclinical model of ASLD, including reduction in the levels of compounds whose elevation are the hallmark of ASLD including plasma citrulline, argininosuccinic acid (ASA) and blood ammonia.
Therefore, auxiliary assays, such as measurements of citrulline and calprotectin in the blood, cytofluorographic examination of peripheral blood immune cells, cytokine profiling, and distinct gene-set-change measurements, are increasingly being used in small bowel transplantation.
When the results of the metabolic screenings that were sent with the pre-diagnosis of metabolic disease were evaluated, two patients with high argininosuccinic acid (ASA) levels in the plasma and urine were diagnosed with argininosuccinic aciduria, and four patients with no evidence of ASA and anhydrides in the blood and urine, but high serum citrulline levels both in the blood and urine were evaluated as citrullinemia Type I (Table II).
Nitric oxide precursors and congenital heart surgery: a randomized controlled trial of oral citrulline.