L-citrulline

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  • Name: L-citrulline
  • Description: L-citrulline is the L-enantiomer of citrulline. It has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor, a protective agent, a nutraceutical, a micronutrient, a human metabolite, an Esc... herichia coli metabolite, a Saccharomyces cerevisiae metabolite and a mouse metabolite. It is an enantiomer of a D-citrulline. It is a tautomer of a L-citrulline zwitterion. It is a non-essential amino acid. In hepatocytes, it is made from L-ornithine and carbamoyl phosphate in one of the central reactions in the urea cycle, the pathway by which mammals excrete ammonia. It is also produced from L-arginine as a by-product of the reaction catalyzed by the enzyme NO synthase. In this reaction, arginine is first oxidized into N(omega)-hydroxyarginine, which is then further oxidized to citrulline concomitant with the release of nitric oxide (EC 1.14.13.39). L-citrulline is converted into L-arginine by the enzymes argininosuccinate synthetase and argininosuccinate lyase in the presence of L-aspartate and ATP. L-citrulline is not involved in protein synthesis and is not one of the amino acids coded for by DNA. Although citrulline cannot be incorporated in proteins during protein synthesis, several proteins are known to contain citrulline as an amino acid. These citrulline residues are generated by a family of enzymes called peptidylarginine deiminases (PADs), which convert the amino acid arginine into citrulline. Proteins that contain citrulline residues include myelin basic protein (MBP), fillagrin and several histone proteins. Its name is derived from citrullus, the Latin word for watermelon (Citrullus vulgaris), from which it was first isolated. The rind of watermelon (Citrullus lanatus) is a good natural source of citrulline. L-Citrulline is found in many foods, some of which are mung bean, cucurbita (gourd), nectarine, and acorn. Citrulline supplements have been claimed to promote energy levels, stimulate the immune system and help detoxify ammonia. (CHEBI:16349, DrugBank ID:DB00155, NCI Thesaurus Code:C53406, FDB011841, HMDB0000904)
Overview of age-variations
Age group comparisons
PMID Age/Age interval, Gender Value (unit of measurement) Method Sample
12768504 Age 32.6 ± 4.4 , Gender ♀ 35.0 (μmol/l) LC blood
12768504 Age 48 ± 4.3, Gender ♀ 37.0 (μmol/l) LC blood
12768504 Age 33.3 ± 3.8, Gender ♂ 39.0 (μmol/l) LC blood
12768504 Age 48.4 ± 6, Gender ♂ 39.0 (μmol/l) LC blood
12768504 Age 75.9 ± 9.3, Gender ♂ 48.0 (μmol/l) LC blood
30113646 Age 44.6 ± 14, Gender ♀ (Dutch) 28.0 (μmol/L) LC-MS/MS plasma
30113646 Age 46.6 ± 13.4, Gender ♂ (Dutch) 29.6 (μmol/L) LC-MS/MS plasma
30113646 Age 43.1 ± 12.7, Gender ♂ (South-Asian Surinamese) 30.1 (μmol/L) LC-MS/MS plasma
30113646 Age 44.6 ± 14, Gender ♀ (Dutch) 110.3 (% (percentage of metabolite concentration compared with baseline (100%) per 10 year increment in age; analyses were adjusted for BMI)) LC-MS/MS plasma
30113646 Age 46.6 ± 13.4, Gender ♂ (Dutch) 104.2 (% (percentage of metabolite concentration compared with baseline (100%) per 10 year increment in age; analyses were adjusted for BMI)) LC-MS/MS plasma
30113646 Age 43.1 ± 12.7, Gender ♂ (South-Asian Surinamese) 108.0 (% (percentage of metabolite concentration compared with baseline (100%) per 10 year increment in age; analyses were adjusted for BMI)) LC-MS/MS plasma
27374292 Age [25–35] (median=32), Gender ♀ (Japanese) 0.850692 (average level of metabolite) UHPLC-MS/MS Positive mode serum
27374292 Age [55–65] (median=60), Gender ♀ (Japanese) 1.060943 (average level of metabolite) UHPLC-MS/MS Positive mode serum
Linear regression
PMID Age/Age interval, Gender Value (unit of measurement) Method Sample
23838602 Age [17–85], Gender ⚥ 0.025 (β) UHPLC/MS/MS serum and plasma
23838602 Age [17–85], Gender ⚥ 2.04 (β) UHPLC/MS/MS serum and plasma
23838602 Age [17–85], Gender ⚥ 1.9 (β) UHPLC/MS/MS serum and plasma
23838602 Age [17–85], Gender ⚥ 1.62 (β) UHPLC/MS/MS serum and plasma
log2 ratio/log2(FC)
PMID Age/Age interval, Gender Value (unit of measurement) Method Sample
Summary
  • Synonym:
    (S)-2-amino-5-ureidopentanoic acid; δ-ureido-L-norvaline; N5-(aminocarbonyl)-L-ornithine; N5-carbamoyl-L-ornithine;L-α-amino-δ-ureidovaleric acid; Nδ-carbamoyl-L-ornithine; L-alpha-amino-delta-ureidovaleric acid; L-citrulline; delta-ureido-L-norvaline; N-delta-carbamoyl-L-ornithine; N-delta-carbamyl-L-ornithine; L-2-amino-5-ureidovaleric acid; Nδ-carbamyl-L-ornithine
  • Chemical Formula:
    C6H13N3O3
  • Exact Mass g/mol:
    175.0956910
  • Systematic name:
    (2S)-2-amino-5-(carbamoylamino)pentanoic acid
  • SMILES:
    C(CC(C(=O)O)N)CNC(=O)N
  • InChI:
    InChI=1S/C6H13N3O3/c7-4(5(10)11)2-1-3-9-6(8)12/h4H,1-3,7H2,(H,10,11)(H3,8,9,12)/t4-/m0/s1
  • InChI Key:
    RHGKLRLOHDJJDR-BYPYZUCNSA-N
  • CAS number:
    372-75-8
Related resources
Pathway info P = product of S = substrate of
Metabolite sources and localization
  • Metabolite location:
    Human organism, Body part, Human body biofluids, Biofluid tissues, Blood, Blood cells, Platelet, Cerebrospinal fluid, Saliva, Sweat, Urine, Organ, Bladder, Intestine, Liver, Placenta, Prostate, Skin, Skin tissue, Epidermis, Tissue, Connective tissue, Connective tissue cell, Fibroblast, Nervous tissue, Nervous tissue cells, Nerve cell, Subcellular level of nervous cells, Myelin sheath, Cellular (general class), Subcellular, Cytoplasm, Mitochondria, Excreta material, Feces
  • Metabolite source:
    Homo sapiens, endogenous metabolite
Age-variations
Age group comparisons
Method: LC
Sample: blood
PubMed PMID: 12768504

Age group comparisons
Method: LC-MS/MS
Sample: plasma
PubMed PMID: 30113646

Age group comparisons
Method: LC-MS/MS
Sample: plasma
PubMed PMID: 30113646

Age group comparisons
Method: UHPLC-MS/MS Positive mode
Sample: serum
PubMed PMID: 27374292
Linear regression
Method: UHPLC/MS/MS
Sample: serum and plasma
PubMed PMID: 23838602
β = 0.025 (y = βx + α)
p-value < 0.05

Linear regression
Method: UHPLC/MS/MS
Sample: serum and plasma
PubMed PMID: 23838602
β = 2.04 (y = βx + α)
p-value < 0.05

Linear regression
Method: UHPLC/MS/MS
Sample: serum and plasma
PubMed PMID: 23838602
β = 1.9 (y = βx + α)
p-value < 0.05

Linear regression
Method: UHPLC/MS/MS
Sample: serum and plasma
PubMed PMID: 23838602
β = 1.62 (y = βx + α)
p-value < 0.05