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C6H13O3N3 An amino acid formed in the synthesis of arginine from ornithine.



(also called α-amino-δ-ureidovaleric acid), H2NCONH(CH2)3CH(NH2)COOH, a natural amino acid.

Citrulline exists in the optically active L- and D-forms and in the racemic DL-form. L-citrulline is found as a free compound in the juice of watermelons and a number of other plants, in the tubers of legumes, and in the tissues of mammals (liver, kidney, brain, muscles, and blood). Citrulline is not a component of natural proteins. Citrulline is separated from enzymatic hydrolysates of casein as a result of arginine splitting. In many organisms, citrulline participates in the ornithine cycle, in which it serves as an intermediate in the biosynthesis of arginine from ornithine. In plants, citrulline also participates in nitrogen fixation.


Meister, A. Biokhimiia aminokislot. Moscow, 1961. (Translated from English.)
Lehninger, A. Biokhimiia: Molekuliarnye osnovy struktury i funktsii kletki. Moscow, 1976. (Translated from English.)
References in periodicals archive ?
Citrulline is a protein released from enterocytes and levels of citrulline show negative correlation with the function of the small bowel graft (33).
5% (all) (all) (all) Amino acid, [micro]mol/L Phenylalanine (a) 54 51 30-97 Tyrosine 79 72 34-151 Isoleucine (a) 30 28 12-66 Leucine (a) 64 60 31-130 Valine (a) 100 95 46-224 Threonine 187 169 66-415 Serine (a) 249 234 130-472 Glycine (a) 350 329 182-637 Methionine 22 21 10-39 Glutamine (a) 495 489 238-808 Glutamate (a) 337 324 193-566 Citrulline (a) 13 12 5-23 Arginine 11 9 <1-36 Ornithine 48 45 19-105 Homocitrulline 1 1 <1-4 Alanine 201 188 104-394 Hydroxyproline 34 33 18-53 Proline (a) 159 155 94-245 Lysine 61 56 29-119 [beta]-Aminoisobutyrate 4 3 <1-16 [beta]-Alanine 8 8 4-15 Sarcosine 1 1 <1-4 [gamma]-Aminobutyrate 2 2 <1-4 Histidine 48 46 24-98 [alpha]-Amino-n-butyrate 18 17 3-39 Steroid 17-OH progesterone, nmol/L 2.
Both arginine and citrulline could reduce exercise-related accumulations of NH3 by increasing the urea cycle (Curis et al.
GBE can significantly down-regulate amino acid metabolism, such as decreased levels of lysine, valine, proline related to oxidative stress, as well as arginine, ornithine and citrulline in urea cycle etc.
Supplementation with 8g citrulline as malate, with 10g sugar (also used in placebo condition) during a weight lifting protocol (perform as many reps as possible until fatigue for multiple sets) able to delay fatigue and promote more reps performed per set for all sets except the first two, and reduced post-workout muscle soreness.
Ingredients include creatine MagnaPower; sustamine; citrulline malate; SOD; superfruit AuroraBlue blueberry; electrolytes; antioxidants; vitamins C, D, B6 and B12; and 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.
Glycine- 789 (normal <505 [micro]mol/L), levels of other amino acids like Alanine, Arginine, Citrulline, Leucine, Methionine, Ornithine, Phenylalanine, Tyrosine & Valine were normal.