What is citrulline?
Advertised as the miraculous molecule for the treatment of impotence, citrulline is actually a "simple" non-essential alpha-type amino acid. The rather funny name of this molecule comes from the Latin citrullus, which means watermelon : not by chance, citrulline was isolated for the first time in watermelon .
Chemical anaslysis
Citrulline expounds its actions mainly in the human metabolic center, the liver.
C 6 H 13 N 3 O 3 is the chemical formula used to identify citrulline, whose IUPAC name is 2-amino-5- (carbamoylamino) pentanoic acid. Although citrulline is a component of some important protein structures (eg histones), it is not encoded by any mRNA molecule. However, it should be pointed out that in light of recent studies citrulline seems to derive from the activity of PADs, calcium-dependent intracellular enzymes: histones with traces of citrulline have been identified as cells unable to reproduce.
Citrulline and urea cycle
As we have seen, citrulline actively participates in the urea cycle: this amino acid is present both in the liver and in the kidney, and favors the elimination of ammonia. Along with ornithine, citrulline is a precursor to arginine. The human organism, starting from ornithine, carbon monoxide and ammonium, is in fact able to synthesize citrulline (by the action of the enzyme ornithine-transcarbamylase ); these amino acids, in combination with aspartic acid, in turn form arginosuccinic acid, subsequently transformed into arginine. [taken from Orthomolecular Medicine: a therapy on a human scale, by A. Panfili]
| Ornithine + carbon monoxide + ammonium → citrulline + aspartic acid → arginosuccinic acid → arginine |
Aphrodisiac molecule
To learn more: Citrulline, Arginine and Erectile Dysfunction - Integration of Citrulline in Sports Practice
Media propaganda promotes citrulline as the aphrodisiac amino acid : in fact, there is a part of the truth. Citrulline, dilating blood vessels, promotes erection; moreover, transformed into arginine in the body, it stimulates both the immune and the cardio-circulatory system, promoting - in the latter case - vasodilation (increased availability of nitric oxide) and improving the elasticity of blood vessels. Precisely for this reason, citrulline is compared to Viagra or Cialis: a good remedy, therefore, for erectile dysfunction.
Citrulline even seems to boast anti-atherosclerotic and protective properties of blood vessels, in addition to increasing the body's metabolic rate, decreasing muscle fatigue and enhancing aerobic performance. Finally, citrulline is able to speed up recovery in the event of psychophysical stress.
Anti-citrulline antibodies
Recently, an anti-citrulline antibody has been isolated, probably useful in the diagnosis of rheumatoid arthritis. Alongside the traditional diagnostic tests of rheumatoid arthritis - which often, among other things, lack of specificity - additional biochemical markers have been identified: among these, the anti-citrulline antibody, also called anti-citrullinated cyclic peptide antibody stands out (anti-CCP).
The anti-CCP assay test is an antibody diagnostic test conducted on blood samples from patients potentially affected by rheumatoid arthritis: the test identifies antibodies against cyclic-citrullinated peptides, which abound in patients with rheumatoid arthritis.
It is right to point out that Science has not yet completely defined the profile of these particular antibodies; however, clinical evidence shows that most rheumatoid arthritis patients have anti-citrulline antibodies.
linfocitisinovialide patients with rheumatoid arthritis synthesize anti-citrulline antibodies.
Summary
Citrulline: to fix the concepts
| Citrulline: etymology | From the Latin citrullus, which means watermelon : not by chance, citrulline was isolated for the first time in watermelon |
| Citrulline: general description | Simple non-essential alpha-type amino acid, implicated in the Macchiavellian urea cycle, involved first of all in the functionality of the immune defenses |
| Citrulline and myths | Advertised as the miraculous molecule for the treatment of impotence: Isolated for the first time in watermelon → watermelon citrulline appears to be the panacea for every male sexual disorder |
| Citrulline: identity card |
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| Citrulline: recent discoveries | Citrulline originates from the activity of PADs, calcium-dependent intracellular enzymes |
| Citrulline: urea cycle | Ornithine + carbon monoxide + ammonium → citrulline + aspartic acid → arginosuccinic acid → arginine |
| Citrulline and erectile dysfunction | Aphrodisiac amino acid, citrulline acts:
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| Citrulline and other functions |
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| Citrulline and anti-citrulline antibodies | Anti-citrulline antibody, also called anti-citrullinated cyclic peptide antibody (anti-CCP) → probably useful in the diagnosis of rheumatoid arthritis Anti-CCP assay assay : antibody diagnostic test performed on blood samples of patients potentially affected by rheumatoid arthritis Conclusions and clinical evidence : most patients with rheumatoid arthritis have anti-citrulline antibodies |
