| L-イソロイシン |
|
|
|
|
別称
2-Amino-3-methylpentanoic acid
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| 識別情報 |
| CAS登録番号 |
73-32-5 |
| PubChem |
791 |
| ChemSpider |
6067 |
| UNII |
04Y7590D77 |
| KEGG |
D00065 |
- CC[C@H](C)[C@@H](C(=O)O)N
|
- InChI=1S/C6H13NO2/c1-3-4(2)5(7)6(8)9/h4-5H,3,7H2,1-2H3,(H,8,9)/t4-,5-/m0/s1
Key: AGPKZVBTJJNPAG-WHFBIAKZSA-N
InChI=1/C6H13NO2/c1-3-4(2)5(7)6(8)9/h4-5H,3,7H2,1-2H3,(H,8,9)/t4-,5-/m0/s1
Key: AGPKZVBTJJNPAG-WHFBIAKZBB
|
| 特性 |
| 化学式 |
C6H13NO2 |
| モル質量 |
131.17 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。 |
イソロイシン (isoleucine) はアミノ酸の一種で2-アミノ-3-メチルペンタン酸（2-アミノ-3-メチル吉草酸）のこと。側鎖に sec-ブチル基を持つ。略号は Ile または I。ロイシンの構造異性体である。「アイソリューシン」と英語読みで音訳される。
疎水性アミノ酸に分類される。蛋白質構成アミノ酸の1つで、必須アミノ酸である。糖原性・ケト原性を持つ。
生合成
2-オキソブタン酸からバリンに類似した経路で、各種酵素によって合成される。すなわち、アセト乳酸シンターゼ (EC 2.2.1.6) およびケトール酸レダクトイソメラーゼ (EC 1.1.1.86) によって生成したジヒドロキシカルボン酸が生成する。次にジヒドロキシ酸デヒドラターゼ (EC 4.2.1.9) の作用により脱水を受けて α-ケトカルボン酸となり、これが分枝鎖アミノ酸アミナーゼ (EC 2.6.1.42) でグルタミン酸からアミノ基を受け取り、イソロイシンが生成する。
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L-イソロイシン (2S,3S) & D-イソロイシン (2R,3R)
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| L-allo-イソロイシン (2S,3R) & D-allo-イソロイシン (2R,3S) |
外部リンク
- イソロイシン - 「健康食品」の安全性・有効性情報 （国立健康・栄養研究所）
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タンパク質を構成するアミノ酸 |
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| 主なトピック |
|
|
|
| 特性 |
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脂肪族
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- 分枝鎖アミノ酸 (バリン
- イソロイシン
- ロイシン)
- メチオニン
- アラニン
- プロリン
- グリシン
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芳香族
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- フェニルアラニン
- チロシン
- トリプトファン
- ヒスチジン
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極性なし
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正電荷 (pKa)
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- リシン (≈10.8)
- アルギニン (≈12.5)
- ヒスチジン (≈6.1)
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|
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負電荷 (pKa)
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- アスパラギン酸 (≈3.9)
- グルタミン酸 (≈4.1)
- システイン (≈8.3)
- チロシン (≈10.1)
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|
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| 分類 |
- 必須アミノ酸
- ケト原性アミノ酸
- 糖原性アミノ酸
- タンパク質を構成しないアミノ酸（英語版）
|
|
| 主要な生体物質：炭水化物（アルコール、糖タンパク質、配糖体） · 脂質（エイコサノイド · 脂肪酸/脂肪酸の代謝中間体 · リン脂質 · スフィンゴ脂質 · ステロイド） · 核酸（核酸塩基 · ヌクレオチド代謝中間体） · タンパク質（タンパク質を構成するアミノ酸/アミノ酸の代謝中間体） · テトラピロール · ヘムの代謝中間体 |
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L-Isoleucine
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| Names |
| IUPAC name
Isoleucine
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| Other names
2-Amino-3-methylpentanoic acid
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| Identifiers |
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CAS Number
|
73-32-5 Y |
| ChEBI |
CHEBI:58045 Y |
| ChemSpider |
6067 Y |
| DrugBank |
DB00167 Y |
|
IUPHAR/BPS
|
3311 |
| Jmol interactive 3D |
Image |
| KEGG |
D00065 Y |
| PubChem |
791 |
| UNII |
04Y7590D77 Y |
InChI
-
InChI=1S/C6H13NO2/c1-3-4(2)5(7)6(8)9/h4-5H,3,7H2,1-2H3,(H,8,9)/t4-,5-/m0/s1 Y
Key: AGPKZVBTJJNPAG-WHFBIAKZSA-N Y
-
InChI=1/C6H13NO2/c1-3-4(2)5(7)6(8)9/h4-5H,3,7H2,1-2H3,(H,8,9)/t4-,5-/m0/s1
Key: AGPKZVBTJJNPAG-WHFBIAKZBB
|
SMILES
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CC[C@H](C)[C@@H](C(=O)O)N
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| Properties |
|
Chemical formula
|
C6H13NO2 |
| Molar mass |
131.18 g·mol−1 |
| Supplementary data page |
|
Structure and
properties
|
Refractive index (n),
Dielectric constant (εr), etc. |
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Thermodynamic
data
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Phase behaviour
solid–liquid–gas |
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Spectral data
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UV, IR, NMR, MS |
| Y verify (what is YN ?) |
| Infobox references |
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Isoleucine (abbreviated as Ile or I) encoded by the codons AUU, AUC, and AUA is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+
3 form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a hydrocarbon side chain, classifying it as a non-polar, uncharged(at physiological pH), aliphatic amino acid. It is essential in humans, meaning the body cannot synthesize it, and must be ingested in our diet. Isoleucine is synthesized from pyruvate employing leucine biosynthesis enzymes in other organisms such as bacteria.[1]
Inability to break down isoleucine, along with other amino acids, is associated with the disease called Maple Syrup Urine Disease, which results in discoloration and a sweet smell in the patient's urine, which is where the name comes from. However in severe cases, MSUD can lead to damage to the brain cells and ultimately death.[2]
Contents
- 1 Metabolism
- 1.1 Biosynthesis
- 1.2 Catabolism
- 2 Nutritional Sources
- 3 Isomers of isoleucine
- 4 Synthesis
- 5 References
- 6 External links
Metabolism
Biosynthesis
As an essential nutrient, it is not synthesized in the body, hence it must be ingested, usually as a component of proteins. In plants and microorganisms, it is synthesized via several steps, starting from pyruvic acid and alpha-ketoglutarate. Enzymes involved in this biosynthesis include:[3]
- Acetolactate synthase (also known as acetohydroxy acid synthase)
- Acetohydroxy acid isomeroreductase
- Dihydroxyacid dehydratase
- Valine aminotransferase
Catabolism
Isoleucine is both a glucogenic and a ketogenic amino acid. After transamination with alpha-ketoglutarate the carbon skeleton can be converted into either Succinyl CoA, and fed into the TCA cycle for oxidation or converted into oxaloacetate for gluconeogenesis (hence glucogenic). It can also be converted into Acetyl CoA and fed into the TCA cycle by condensing with oxaloacetate to form citrate. In mammals Acetyl CoA cannot be converted back to carbohydrate but can be used in the synthesis of ketone bodies or fatty acids, hence ketogenic.
Biotin, sometimes referred to as Vitamin B7 or Vitamin H, is an absolute requirement for the full catabolism of isoleucine (as well as leucine). Without adequate biotin, the human body will be unable to fully break down isoleucine and leucine molecules.[4] This can lead to numerous physiological issues (related to muscle maintenance and protein synthesis, lipid metabolism, and fatty acid metabolism) as well as cognitive issues resulting from general metabolic pathway failure and the irritating effects of hydroxyisovalerate, a byproduct of incomplete isoleucine catabolism. Isovaleric acidemia is an example of a disorder caused by incomplete catabolism of leucine.[citation needed]
Nutritional Sources
Even though this amino acid is not produced in animals, it is stored in high quantities. Foods that have high amounts of isoleucine include eggs, soy protein, seaweed, turkey, chicken, lamb, cheese, and fish.[5]
Isomers of isoleucine
| Forms of Isoleucine |
| Common name: |
isoleucine |
D-isoleucine |
L-isoleucine |
DL-isoleucine |
allo-D-isoleucine |
allo-L-isoleucine |
allo-DL-isoleucine |
| Synonyms: |
|
(R)-Isoleucine |
L(+)-Isoleucine |
(R*,R*)-isoleucine |
|
alloisoleucine |
|
| PubChem: |
CID 791 from PubChem |
CID 94206 from PubChem |
CID 6306 from PubChem |
CID 76551 from PubChem |
|
|
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| EINECS number: |
207-139-8 |
206-269-2 |
200-798-2 |
|
216-143-9 |
216-142-3 |
221-464-2 |
| CAS number: |
443-79-8 |
319-78-8 |
73-32-5 |
|
1509-35-9 |
1509-34-8 |
3107-04-8 |
|
L-isoleucine (2S,3S) and D-isoleucine (2R,3R)
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| L-allo-isoleucine (2S,3R) and D-allo-isoleucine (2R,3S) |
Synthesis
Isoleucine can be synthesized in a multistep procedure starting from 2-bromobutane and diethylmalonate.[6] Synthetic isoleucine was originally reported in 1905.[7]
German chemist Felix Ehrlich discovered isoleucine in hemoglobin in 1903.
References
- ^ Kisumi, M; Komatsubara, S; Chibata, I (Jul 1977). "Pathway for isoleucine formation form pyruvate by leucine biosynthetic enzymes in leucine-accumulating isoleucine revertants of Serratia marcescens.". J. Biochem. PMID 142769.
- ^ "Maple Syrup Urine Disease (MSUD)". learn.genetics.utah.edu. Retrieved 2015-12-08.
- ^ Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.
- ^ "Biotin & Detoxification Needs in Cognitively Delayed Adult - Metametrix Learning Center". Metametrix.com. Retrieved 2013-10-18.
- ^ [1], List is in order of highest to lowest of per 200 Calorie serving of the food, not volume or weight.
- ^ "dl-Isoleucine". Org. Synth. 1955. ; Coll. Vol. 3, p. 495
- ^ Bouveault and Locquin, Compt. rend., 141, 115 (1905).
External links
- Food Sources of Isoleucine
- Isoleucine and valine biosynthesis
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The encoded amino acid
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| General topics |
- Protein
- Peptide
- Genetic code
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| By properties |
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Aliphatic
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- Branched-chain amino acids (Valine
- Isoleucine
- Leucine)
- Methionine
- Alanine
- Proline
- Glycine
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Aromatic
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- Phenylalanine
- Tyrosine
- Tryptophan
- Histidine
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Polar, uncharged
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- Asparagine
- Glutamine
- Serine
- Threonine
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Positive charge (pKa)
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- Lysine (≈10.8)
- Arginine (≈12.5)
- Histidine (≈6.1)
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Negative charge (pKa)
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- Aspartic acid (≈3.9)
- Glutamic acid (≈4.1)
- Cysteine (≈8.3)
- Tyrosine (≈10.1)
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| Other classifications |
- Essential amino acid
- Ketogenic amino acid
- Glucogenic amino acid
- Non-proteinogenic amino acid
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Amino acid metabolism metabolic intermediates
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| K→acetyl-CoA |
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lysine→
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- Saccharopine
- Allysine
- α-Aminoadipic acid
- α-Ketoadipate
- Glutaryl-CoA
- Glutaconyl-CoA
- Crotonyl-CoA
- β-Hydroxybutyryl-CoA
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leucine→
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- α-Ketoisocaproic acid
- Isovaleryl-CoA
- 3-Methylcrotonyl-CoA
- 3-Methylglutaconyl-CoA
- HMG-CoA
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tryptophan→alanine→
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- N'-Formylkynurenine
- Kynurenine
- Anthranilic acid
- 3-Hydroxykynurenine
- 3-Hydroxyanthranilic acid
- 2-Amino-3-carboxymuconic semialdehyde
- 2-Aminomuconic semialdehyde
- 2-Aminomuconic acid
- Glutaryl-CoA
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| G |
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G→pyruvate→citrate
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glycine→serine→
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- glycine→creatine: Glycocyamine
- Phosphocreatine
- Creatinine
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G→glutamate→
α-ketoglutarate
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histidine→
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- Urocanic acid
- Imidazol-4-one-5-propionic acid
- Formiminoglutamic acid
- Glutamate-1-semialdehyde
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proline→
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- 1-Pyrroline-5-carboxylic acid
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arginine→
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- Agmatine
- Ornithine
- Cadaverine
- Putrescine
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other
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- cysteine+glutamate→glutathione: γ-Glutamylcysteine
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G→propionyl-CoA→
succinyl-CoA
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valine→
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- α-Ketoisovaleric acid
- Isobutyryl-CoA
- Methacrylyl-CoA
- 3-Hydroxyisobutyryl-CoA
- 3-Hydroxyisobutyric acid
- 2-Methyl-3-oxopropanoic acid
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|
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isoleucine→
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- 2,3-Dihydroxy-3-methylpentanoic acid
- 2-Methylbutyryl-CoA
- Tiglyl-CoA
- 2-Methylacetoacetyl-CoA
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methionine→
|
- generation of homocysteine: S-Adenosyl methionine
- S-Adenosyl-L-homocysteine
- Homocysteine
- conversion to cysteine: Cystathionine
- alpha-Ketobutyric acid+Cysteine
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threonine→
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propionyl-CoA→
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G→fumarate
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phenylalanine→tyrosine→
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- 4-Hydroxyphenylpyruvic acid
- Homogentisic acid
- 4-Maleylacetoacetic acid
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G→oxaloacetate
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| Other |
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