Arginine 63550 221758810 2008-06-25T23:36:50Z DOI bot 6652755 Citation maintenance. Added: doi_brokendate. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. {{NatOrganicBox | image= [[Image:Arginin - Arginine.svg|250px|Skeletal structure of <small>L</small>-arginine]]<br><br> [[Image:L-arginine-3D-hztl.png|200px|3D structure of <small>L</small>-arginine]]<br />Chemical structure of L-arginine | name=2-amino-5-(diaminomethylidene<br />amino)pentanoic acid | PubChem = 6322 | CAS = 74-79-3 | SMILES = N[C@@H](CCCNC(N)=N)C(O)=O | C=6 | H=14 | N=4 | O=2 | mass=174.2 g/mol }} '''Arginine''' (abbreviated as '''Arg''' or '''R''')<ref>{{cite web | author=IUPAC-IUBMB Joint Commission on Biochemical Nomenclature | title=Nomenclature and Symbolism for Amino Acids and Peptides | work=Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc | url=http://www.chem.qmul.ac.uk/iupac/AminoAcid/ | accessdate=2007-05-17}}</ref> is an α-[[amino acid]]. The [[Optical isomerism|<small>L</small>-form]] is one of the 20 most common natural amino acids. Its [[codons]] are CGU, CGC, CGA, CGG, AGA, and AGG. In mammals, arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual. Infants are unable to meet their requirements and thus arginine is nutritionally essential for infants. Arginine was first isolated from a [[lupin]] seedling extract in 1886 by the Swiss chemist Ernst Schultze. ==Structure== Arginine consists of a 4-carbon [[aliphatic]] straight chain, the distal end of which is capped by a complex [[guanidine|guanidinium]] group. With a [[Acid_dissociation_constant|p''K''<sub>a</sub>]] of 12.48, the guanidinium group is positively charged in neutral, acidic and even most basic environments, and thus imparts [[Basic (chemistry)|basic]] chemical properties to arginine. Because of the [[Conjugated system|conjugation]] between the double bond and the nitrogen lone pairs, the positive charge is de-localized, enabling the formation of multiple [[Hydrogen bond|H-bonds]]. ==Sources== ===Dietary Sources=== Arginine is a [[essential amino acid|nonessential amino acid]], meaning it can be manufactured by the human body, and does not need to be obtained directly through the diet. The biosynthetic pathway however does not produce sufficient arginine, and some must still be consumed through diet. Individuals who have poor nutrition or certain physical conditions are advised to supplement their diet with L-Arginine or increase their intake of foods containing arginine. Arginine is found in a wide variety of foods, including<ref>{{cite web|url=http://www.keysupplements.com/articles/L-Arginine-Supplements-Nitric-Oxide-Scientific-Studies.htm |title=L-Arginine Supplements Nitric Oxide Scientific Studies Food Sources |accessdate=2007-02-20}}</ref>: * '''Animal sources''': dairy products (e.g. [[cottage cheese]], [[ricotta]], [[milk]], [[yogurt]], whey protein drinks), [[beef]], [[pork]] (e.g. bacon, ham), [[poultry]] (e.g. chicken and turkey light meat), [[wild game]] (e.g. pheasant, quail), [[seafood]] (e.g. halibut, lobster, salmon, shrimp, snails, tuna in water) * '''Vegan sources''': [[wheat germ]] and flour, buckwheat, [[granola]], [[oatmeal]], [[nut (fruit)|nuts]] (coconut, pecans, cashews, walnuts, almonds, Brazil nuts, hazel nuts, pine nuts, peanuts), [[seeds]] (pumpkin, sesame, sunflower), [[chick peas]], cooked [[soybeans]], [[chocolate]] * '''Other''': some [[energy drinks]] and body building supplements ===Biosynthesis=== Arginine is synthesized from [[citrulline]] by the sequential action of the cytosolic enzymes [[argininosuccinate synthetase]] (ASS) and [[argininosuccinate lyase]] (ASL). This is energetically costly, as the synthesis of each molecule of argininosuccinate requires hydrolysis of [[adenosine triphosphate]] (ATP) to [[adenosine monophosphate]] (AMP); i.e., two ATP equivalents. Citrulline can be derived from multiple sources: * from arginine via [[nitric oxide synthase]] (NOS); * from [[ornithine]] via catabolism of [[proline]] or [[glutamine]]/[[glutamate]]; * from [[asymmetric dimethylarginine]] (ADMA) via DDAH. The pathways linking arginine, [[glutamine]], and [[proline]] are bidirectional. Thus, the net utilization or production of these amino acids is highly dependent on cell type and developmental stage. On a whole-body basis, synthesis of arginine occurs principally via the intestinal–renal axis, wherein [[epithelial cell]]s of the [[small intestine]], which produce [[citrulline]] primarily from [[glutamine]] and [[glutamate]], collaborate with the [[proximal tubule cell]]s of the [[kidney]], which extract citrulline from the circulation and convert it to arginine, which is returned to the circulation. Consequently, impairment of small bowel or renal function can reduce endogenous arginine synthesis, thereby increasing the dietary requirement. Synthesis of arginine from citrulline also occurs at a low level in many other cells, and cellular capacity for arginine synthesis can be markedly increased under circumstances that also induce [[Nitric oxide synthase|iNOS]]. Thus, citrulline, a coproduct of the NOS-catalyzed reaction, can be recycled to arginine in a pathway known as the '''citrulline-NO''' or '''arginine-citrulline pathway'''. This is demonstrated by the fact that in many cell types, citrulline can substitute for arginine to some degree in supporting NO synthesis. However, recycling is not quantitative because citrulline accumulates along with nitrate and nitrite, the stable end-products of NO, in NO-producing cells.<ref>[[Image:Free review.png]] Enzymes of arginine metabolism ''J Nutr. 2004 Oct; 134(10 Suppl): 2743S-2747S; PMID 15465778'' [http://www.nutrition.org/cgi/content/full/134/10/2743S Free text]</ref> ==Function== Arginine plays an important role in cell division, the healing of wounds, removing ammonia from the body, immune function, and the release of hormones. Arginine, taken in combination with [[proanthocyanidin]]s<ref>Stanislavov, R. and Nikolova. 2003. Treatment of Erectile Dysfunction with Pycnogenol and L-arginine. Journal of Sex and Marital Therapy, 29(3): 207 – 213.</ref> or [[yohimbine]]<ref>Lebret, T., Hervéa, J. M., Gornyb, P., Worcelc, M. and Botto, H. 2002. Efficacy and Safety of a Novel Combination of L-Arginine Glutamate and Yohimbine Hydrochloride: A New Oral Therapy for Erectile Dysfunction. European Urology 41(6): 608-613.</ref>, has also been used as a treatment for [[erectile dysfunction]]. The benefits and functions attributed to oral ingestion of L-arginine include: * Precursor for the synthesis of Nitric Oxide (NO) <br /> * Stimulation of the release of the most important anti-aging hormone in the body, growth hormone. <br /> * Improves immune function <br /> * Reduces healing time of injuries (particularly bone) <br /> * Reduces risk of heart disease <br /> * Increases muscle mass <br /> * Reduces adipose tissue body fat <br /> * Helps improve insulin sensitivity <br /> * Helps decrease blood pressure <br /> * Alleviates male infertility, improving sperm production and motility <br /> * Increases circulation throughout the body, including the sex organs ===In proteins=== The geometry, charge distribution and ability to form multiple H-bonds make arginine ideal for binding negatively charged groups. For this reason arginine prefers to be on the outside of the proteins where it can interact with the polar environment. Incorporated in proteins, arginine can also be converted to citrulline by PAD enzymes. In addition, arginine can be [[Methylation|methylated]] by protein methyltransferases. ===As a precursor=== Arginine is the immediate precursor of [[Nitric oxide|NO]], urea, ornithine and agmatine; is necessary for the synthesis of [[creatine]]; and can also be used for the synthesis of polyamines (mainly through ornithine and to a lesser degree through agmatine), citrulline, and glutamate. For being a precursor of NO, (relaxes blood vessels), arginine is used in many conditions where [[vasodilation]] is required. The presence of [[asymmetric dimethylarginine]] (ADMA), a close relative, inhibits the nitric oxide reaction; therefore, ADMA is considered a marker for [[vascular disease]], just as L-arginine is considered a sign of a healthy [[endothelium]]. ===Treatment of herpes simplex virus=== A low ratio of arginine to lysine may be of benefit in the treatment of herpes simplex virus. For more information, refer to [[Herpes#Treatment|Herpes - Treatment]]. ===Possible increases in risk of death from heart disease=== A clinical trial found that patients taking an L-arginine supplement following a heart attack didn't improve in their vascular tone or their hearts' ability to pump. In fact, more patients died who were taking L-arginine than placebo and the study was stopped early with the recommendation the supplement not be used by heart attack patients. The supplement still is widely marketed.<ref>[http://www.sciencedaily.com/releases/2008/01/080131161759.htm Medical College of Georgia. "Diabetes Makes It Hard For Blood Vessels To Relax." ScienceDaily 1 February 2008. 1 February 2008]</ref><ref>Arginine Therapy in Acute Myocardial Infarction ''JAMA. 2006 Jan; Vol.295 #1: 58-64; PMID 16391217'' [http://jama.ama-assn.org/cgi/content/short/295/1/58 Abstract]</ref><ref>This study has been discussed in some detail in : "Reverse Heart Disease Now" by Stephen T Sinatra MD and James C Roberts MD, publ. Wiley 2006 ISBN 0-471-74704-1 at pp 111-113.</ref> ===Growth hormone=== Arginine increases the production of [[growth hormone]].<ref>{{cite journal |author=Alba-Roth J, Müller O, Schopohl J, von Werder K |title=Arginine stimulates growth hormone secretion by suppressing endogenous somatostatin secretion |journal=J Clin Endocrinol Metab |volume=67 |issue=6 |pages=1186–9 |year=1988 |pmid=2903866 |doi=10.1126/science.2237411.<br> |doi_brokendate=2008-06-25}}</ref> Reports of its effects on male muscular development ===Prolactin=== Although there haven't been thorough studies, some sources claim that arginine helps release [[prolactin]], an estrogenic compound which is associated with lactation, and like all estrogenic compounds may curb the secretion of testosterone{{Fact|date=August 2007}}. Thus some bodybuilders stay away from pure arginine, intaking only amounts naturally found in protein. ==References== {{reflist|2}} == External links == *[http://webbook.nist.gov/cgi/cbook.cgi?ID=C74793&Units=SI&Mask=4#Thermo-Phase NIST Chemistry Webbook] *[http://www.larginine.net L-Arginine] {{AminoAcids}} [[Category:Proteinogenic amino acids]] [[Category:Glucogenic amino acids]] [[Category:Basic amino acids]] [[Category:Essential amino acids]] [[Category:Guanidines]] [[ca:Arginina]] [[cs:Arginin]] [[de:Arginin]] [[es:Arginina]] [[eo:Arginino]] [[fr:Arginine]] [[ko:아르기닌]] [[hr:Arginin]] [[id:Arginin]] [[it:Arginina]] [[he:ארגינין]] [[lv:Arginīns]] [[lb:Arginin]] [[lt:Argininas]] [[nl:Arginine]] [[ja:アルギニン]] [[ps:آرګېنين]] [[pl:Arginina]] [[pt:Arginina]] [[ru:Аргинин]] [[sk:Arginín]] [[fi:Arginiini]] [[sv:Arginin]] [[tr:Arginin]] [[uk:Аргінін]] [[zh:精氨酸]]