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L-アルギニン | |
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IUPAC名
(S)-2-Amino-5-guanidinopentanoic acid |
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別称
Arginine
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識別情報 | |
CAS登録番号 | 74-79-3 |
PubChem | 6322 |
ChemSpider | 227 |
UNII | 94ZLA3W45F |
KEGG | C00062 |
ChEMBL | CHEMBL179653 |
IUPHAR/BPS
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721 |
SMILES
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InChI
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特性 | |
化学式 | C6H14N4O2 |
モル質量 | 174.2 g mol−1 |
特記なき場合、データは常温 (25 °C)・常圧 (100 kPa) におけるものである。 |
アルギニン (arginine) は天然に存在するアミノ酸のひとつ。2-アミノ-5-グアニジノペンタン酸(2-アミノ-5-グアニジノ吉草酸)のこと。略号は R あるいは Arg。示性式 H2NC(=NH)NH(CH2)3CH(NH2)COOH で表される。英発音に基づき、アージニンともいう。
荷電極性側鎖アミノ酸。塩基性アミノ酸の一種で、蛋白質を構成するアミノ酸としては最も塩基性が高い[1]。非必須アミノ酸ではあるが、成長期には摂取が必要。糖原性を持つ。
尿素回路の中間体であり[1]、投与によりアンモニアの生体内解毒を助ける。尿素回路内で、アルギナーゼ (EC 3.5.3.1) によりオルニチンと尿素に分解される。アルギナーゼの欠損により高アルギニン血症になる。
条件付必須アミノ酸の1つ。外傷・褥瘡・感染などの侵襲下においては、充分な補給が望ましいとされる。免疫反応の活性化、細胞増殖を促進し、コラーゲン生成促進などにより、創傷や褥瘡の治癒を促す。
ヒストンやプロタミンといった、核蛋白質での含量が高く、魚類プロタミンでは全体の3分の2がアルギニンになっている。食物では、肉類、ナッツ、大豆、玄米、レーズン、エビ、牛乳などに多く含まれる。
クエン酸回路のケトグルタル酸からアルギニンの生合成が始まる。ケトグルタル酸からグルタミン酸が合成され、N-アセチルグルタメートに変換され、この物質がN-アセチルグルタメートキナーゼによりN-アセチルグルタメートリン酸へと変換させる。次に、N-アセチルグルタメートリン酸はオルニチンに変換され、オルニチントランスカルバミラーゼによりシトルリンに変換された後、アルギニンとなる。
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ウィキメディア・コモンズには、アルギニンに関連するカテゴリがあります。 |
Names | |
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Other names
2-Amino-5-guanidinopentanoic acid
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Identifiers | |
CAS Number
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3D model (Jmol)
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3DMet | B01331 |
Beilstein Reference
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1725411, 1725412 R, 1725413 S |
ChEBI |
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ChemSpider |
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DrugBank |
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ECHA InfoCard | 100.000.738 |
EC Number | 230-571-3 |
Gmelin Reference
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364938 R |
IUPHAR/BPS
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KEGG |
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MeSH | Arginine |
PubChem CID
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RTECS number | CF1934200 S |
UNII |
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InChI
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SMILES
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Properties | |
Chemical formula
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C6H14N4O2 |
Molar mass | 174.20 g·mol−1 |
Appearance | White crystals |
Odor | Odourless |
Melting point | 260 °C; 500 °F; 533 K |
Boiling point | 368 °C (694 °F; 641 K) |
Solubility in water
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14.87 g/100 mL (20 °C) |
Solubility | slightly soluble in ethanol insoluble in ethyl ether |
log P | −1.652 |
Acidity (pKa) | 12.488 |
Basicity (pKb) | 1.509 |
Thermochemistry | |
Specific
heat capacity (C) |
232.8 J K−1 mol−1 (at 23.7 °C) |
Std molar
entropy (S |
250.6 J K−1 mol−1 |
Std enthalpy of
formation (ΔfH |
−624.9–−622.3 kJ mol−1 |
Std enthalpy of
combustion (ΔcH |
−3.7396–−3.7370 MJ mol−1 |
Pharmacology | |
ATC code
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B05XB01 (WHO) S |
Hazards | |
Safety data sheet | See: data page sigma-aldrich |
GHS pictograms | |
GHS signal word | WARNING |
GHS hazard statements
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H319 |
GHS precautionary statements
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P305+351+338 |
EU classification (DSD)
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Xi |
R-phrases | R36 |
S-phrases | S26 |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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5110 mg/kg (rat, oral) |
Related compounds | |
Related alkanoic acids
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Related compounds
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Supplementary data page | |
Structure and
properties |
Refractive index (n), Dielectric constant (εr), etc. |
Thermodynamic
data |
Phase behaviour solid–liquid–gas |
Spectral data
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UV, IR, NMR, MS |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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N verify (what is YN ?) | |
Infobox references | |
Arginine (abbreviated as Arg or R) encoded by the codons CGU, CGC, CGA, CGG, AGA, and AGG[1] is an α-amino acid that is used in the biosynthesis of proteins.
Arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual.[2] Preterm infants are unable to synthesize or create arginine internally, making the amino acid nutritionally essential for them.[3] Most healthy people do not need to supplement with arginine because their body produces sufficient amounts.[4]
Arginine was first isolated from a lupin seedling extract in 1886 by the German chemist Ernst Schultze.[5] It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain of a 3-carbon aliphatic straight chain capped by a complex guanidinium, classifying it as a charged (at physiological pH), aliphatic amino acid.
A conditionally essential amino acid is one that may be required depending on the health status or life cycle of the individual. Arginine is one such conditionally essential amino acid. The biosynthetic pathway, however, does not produce sufficient arginine, and some must still be consumed through diet.[citation needed] Individuals with poor nutrition or certain physical conditions may be advised to increase their intake of foods containing arginine. Arginine is found in a wide variety of foods, including:
Arginine is synthesized from citrulline in arginine and proline metabolism by the sequential action of the cytosolic enzymes argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL). In terms of energy, this is costly, as the synthesis of each molecule of argininosuccinate requires hydrolysis of adenosine triphosphate (ATP) to adenosine monophosphate (AMP), i.e., two ATP equivalents. In essence, taking an excess of arginine gives more energy by saving ATPs that can be used elsewhere.
Citrulline can be derived from multiple sources:
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 cells of the small intestine, which produce citrulline primarily from glutamine and glutamate, collaborate with the proximal tubule cells of the kidney, which extract citrulline from the circulation and convert it to arginine, which is returned to the circulation. As a consequence, 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 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.[6]
Arginine plays an important role in cell division, the healing of wounds, removing ammonia from the body, immune function, and the release of hormones.[2][7][8]
The roles of arginine include:
The distributing basics of the moderate structure found in 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 methylated by protein methyltransferases.
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. As a precursor of nitric oxide, arginine may have a role in the treatment of some conditions where vasodilation is required.[2] 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.
Industry founded studies have shown arginine (8%) in dental products (e.g., toothpaste) provides effective relief from sensitive teeth by depositing a dentin-like mineral, containing calcium and phosphate, within the dentin tubules and in a protective layer on the dentin surface, though conflict of interest of authors and methodology flaws casts doubts on the validity of the findings.[17][18]
An unproven claim is that 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 also see journal article.[19]
A number of studies have shown that L-arginine can have a positive effect in reducing the pain associated with peripheral neuropathy. As the immediate precursor of Nitric Oxide, increased L-arginine intake sets off a cascade of bio-chemical events that ultimately leads to increased blood perfusion in the areas affected by the disease. As more nutrient-rich, oxygenated blood becomes available to the damaged nerve cells, inflammation is reduced and the cells can begin to regenerate. Most studies show L-arginine efficacy in treating peripheral neuropathy is best accomplished with a daily intake of 500 mg to 1000 mg.
L-arginine is generally recognized as safe (GRAS-status) at intakes of up to 20 g/d.[20]
The amino acid side-chain of arginine consists of a 3-carbon aliphatic straight chain, the distal end of which is capped by a complex guanidinium group.
With a pKa of 12.48, the guanidinium group is positively charged in neutral, acidic, and even most basic environments, and thus imparts basic chemical properties to arginine. Because of the conjugation between the double bond and the nitrogen lone pairs, the positive charge is delocalized, enabling the formation of multiple H-bonds.
This section needs more medical references for verification or relies too heavily on primary sources. Please review the contents of the section and add the appropriate references if you can. Unsourced or poorly sourced material may be challenged and removed. (May 2016) |
Intravenously-administered arginine stimulates the secretion of growth hormone,[21] and is used in growth hormone stimulation tests.[22] Two studies have found that oral arginine supplementation is also effective at increasing resting GH levels. The first study found that oral preparations of arginine are effective at increasing growth hormone levels. In fact, the 9-gram dose resulted in mean peak GH levels of 6.4 (± 1.3) µg/L versus placebo levels of 2.9 (± 0.7).[23] Another study found similar results. It included resting versus exercise and oral L-arginine versus oral placebo. The authors concluded that "Oral arginine alone (7 g) stimulated GH release, but a greater GH response was seen with exercise alone. The combined effect of arginine before exercise attenuates the GH response… GH production: Ex > Arg+Ex > Arg > placebo" suggesting against supplementing with arginine alone prior to exercise if the goal is to raise GH levels, but concurring with the previous study that oral L-arginine increases GH on days free of significant exercise.[24] In contrast to these two studies that found increased resting GH due to oral arginine supplementation, a third study did not find increase in resting GH levels from oral supplementation. In that study, oral preparations of L-arginine were ineffective at increasing growth hormone levels despite being effective at increasing plasma levels of L-arginine.[25]
Several trials delved into effects of L-arginine in MELAS syndrome, a mitochondrial disease.[26]
Intravenous infusion of arginine reduces blood pressure in patients with hypertension as well as normal subjects.[27]
A meta-analysis showed that L-arginine reduces blood pressure with pooled estimates of 5.4/2.7 mmHg for SBP/DBP.[12]
Supplementation with L-arginine reduces diastolic blood pressure and lengthens pregnancy for women with gestational hypertension, including women with high blood pressure as part of pre-eclampsia.[28] It does not lower systolic blood pressure or improve the baby's weight at birth.
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(help)Wikimedia Commons has media related to arginine. |
The encoded amino acid
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Amino acid metabolism metabolic intermediates
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Nitric oxide signaling modulators
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NO donors (prodrugs) |
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See also: Receptor/signaling modulators
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Authority control |
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リンク元 | 「オルニチン回路」「アルギニン」「L-arginine」 |
拡張検索 | 「NG-monomethyl-L-arginine」「hyperargininemia」「des-arginine complement C5a」 |
1) アンモニア + 炭酸 + 2ATP → ADP + Pi + カルバモイルリン酸 5)から ↓ 2) カルバモイルリン酸 + オルニチン → シトルリン + Pi ↓ 3)へ
2)から ↓ 3) シトルリン + アスパラギン酸 + ATP → AMP + ピロリン酸 + アルギニノコハク酸 4) アルギニノコハク酸 → フマル酸 + アルギニン 5) アルギニン + 水 → 尿素 + オルニチン ↓ 2)へ
| ornithine | ----------mitochondria | ornithine | |<-carbamoyl phosphate {ornithine transcarbamoylase} | citrulline | ----------mitochondria | citrulline | |<-aspartate {argininosuccinate synthase} | argininosuccinate | |->fumarate {argininosuccinase} | arginine | |<-H2O | {arginase} |->urea | ornithine |
-CH2-CH2-CH2-NH-C-(NH2)NH
.