L-アスパラギン 化学特性,用途語,生産方法
外観
無色澄明の液体
定義
本品は、次の化学式で表されるアミノ酸である。
溶解性
水及びエタノールと任意の割合で混和する.
解説
2-aminosuccinamic acid．C4H8N2O3(132.12)．H2NCOCH2CH(NH2)COOH．略号AsnまたはN．アスパラガスからはじめて見いだされたが，L-アスパラギンはマメ類やテンサイに多く含まれ，タンパク質の構成成分としても広く分布している．豆モヤシの温水抽出液から一水和物が得られる．一水和物は斜方晶系．融点234～235 ℃．[α]20D－5.42°(水)．pKa1 2.02，pKa2 8.80．水に易溶，エタノールに難溶．苦味がある．生体中で過剰の窒素を貯蔵する役割がある．必須アミノ酸ではない．D,L-アスパラギンは無水マレイン酸をアンモニア水と加熱して合成する．森北出版「化学辞典（第2版）
用途
アミノ酸自動分析計用の標準液。
化粧品の成分用途
ヘアコンディショニング剤、皮膚コンディショニング剤
説明
Asparagine (abbreviated as Asn or N) is one of the 20 most common natural amino acids on Earth. It has carboxamide as the sidechain's functional group. It is not an essential amino acid. Its codons are AAU and AAC.
The amino acid L-asparagine is a structural analog of L-aspartic acid, where the side chain of the carboxylic acid moiety is amidated, to give a terminal amine group. This renders L-asparagine neutral at physiological pH. The amide group of asparagine is derived from glutamate, in the reaction of aspartate and glutamine in the presence of ATP to yield asparagine and glutamate. In vivo, asparagine is hydrolyzed to aspartate and NH4+ by asparaginase. Asparagine is also an important amino acid in glycopeptide bonds, via N-glycosyl linkages to the sugar rings.
化学的特性
White crystal or crystalline powder with a slightly sweet taste. Slightly soluble in water, insoluble in ethanol and ether, it often exists as a monohydrate, and it is a rhombic hemihedral crystals. The melting point is 234-235°C , and the aminocarbonyl reaction is carried out by co-heating with sugar, which can form special aroma substances. The best recrystallization method is water, followed by ethanol. In case of alkali hydrolysis into aspartic acid. Heating its aqueous solution also decomposes. Natural products exist in various legumes and the like.
物理的性質
Solubility 3.11 (28 ℃) g/100 g H2O, pI 5.41, dissociation constants: pK1 2.02, pK2 8.8.
天然物の起源
Dietary sourcesAsparagine is not essential for humans, which means that it can be synthesized from central metabolic pathway intermediates and is not required in the diet. Asparagine is found in :
Animal sources : dairy, whey, beef, poultry, eggs, fish, lactalbumin , sea food
Plant sources : asparagus, potatoes, legumes, nuts, seeds, soy, whole grains.
BiosynthesisThe precursor to asparagine is oxaloacetate. Oxaloacetate is converted to aspartate using a transaminase enzyme. The enzyme transfers the amino group from glutamate to oxaloacetate producing α- ketoglutarate and aspartate. The enzyme asparagine synthetase produces asparagine, AMP, glutamate, and pyrophosphate from aspartate, glutamine, and ATP. In the asparagine synthetase reaction, ATP is used to activate aspartate, forming β-aspartyl-AMP. Glutamine donates an ammonium group, which reacts with β-aspartyl-AMP to form asparagine and free AMP.
来歴
Asparagine was first isolated in 1806, under a crystalline form, by French chemists Louis Nicolas Vauquelin and Pierre Jean Robiquet (then a young assistant) from asparagus juice, in which it is abundant — hence, the name they chose for that new matter — becoming the first amino acid to be isolated.
A few years later, in 1809, Pierre Jean Robiquet again identified, this time from liquorice root, a substance with properties he qualified as very similar to those of asparagine, that Plisson in 1828 identified as asparagine itself.
使用
L-asparagine has been used:
to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals.
to study the effects of amino acids in promoting food consumption in Drosophila melanogaster.
to study non-enzymatic gluconeogenesis.
L-Asparagine is used in cell culture media and is a component of MEM non-essential amino acids solution.
L-Asparagine has been shown to enhance ornithine decarboxylase activity in cultured human colon adenocarcinoma Caco-2 cells and in cultured IEC-6 intestinal epithelial cells. Spore germination in Bacillus subtilis has been increased in the presence of L-asparagine.
An isoxazoline RGD mimic platelet GPIIb/IIIa antagonist has been prepared by chiral synthesis with L-asparagine as a starting material. L-Asparagine has been utilized in the synthesis of 4-azalysine building blocks for application to combinatorial chemistry.
調製方法
A simple synthesis of L -asparagine starts from L -aspartic acid which is esterified to the b-methyl ester followed by treatment with ammonia.
定義
ChEBI: L-asparagine is an optically active form of asparagine having L-configuration. It has a role as a nutraceutical, a micronutrient, a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite, a mouse metabolite and a plant metabolite. It is an aspartate family amino acid, a proteinogenic amino acid, an asparagine and a L-alpha-amino acid. It is a conjugate base of a L-asparaginium. It is a conjugate acid of a L-asparaginate. It is an enantiomer of a D-asparagine. It is a tautomer of a L-asparagine zwitterion.
生物学の機能
Asparagine is a dietarily dispensable amino acid synthesized from aspartate and glutamine. Asparagine has three major functions: 1) incorporation into amino acid sequences of proteins; 2) storage form for aspartate (is a required precursor for synthesis of DNA, RNA and ATP); and 3) source of amino groups for production of other dispensable amino acids via trasaminases.
The nervous system requires asparagine. It also plays an important role in the synthesis of ammonia.
The addition of N-acetyl glucosamine to asparagine is performed by oligosaccharyltransferase enzymes in the endoplasmic reticulum. This glycosylation is important both for protein structure and protein function.
生合成
図2. アスパラギンの生合成
生体内においては、アスパラギンシンテターゼによりアスパラギン酸から生合成されます。
使用用途
アスパラギンは、アミノ酸の一種でありヒトの体内に存在している物質になります。そのため、比較的安全性の高い物質といえます。このアスパラギンは食品添加物の分類で使用されることがあります。
また、TCA回路に働きかけてエネルギーの代謝を促進するという点から、低タンパク血症や低栄養状態の方にアミノ酸を補給する目的で医薬品として使用される場合もあります。
安全性プロファイル
When heated to
decomposition emits toxic fumes of Nox
概要
最初に発見されたアミノ酸で，アスパラから単離された
純化方法
Likely impurities are aspartic acid and tyrosine. Crystallise it from H2O or aqueous EtOH. It slowly effloresces in dry air. [Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 p 1856 1961, Beilstein 4 IV 3005.]
L-アスパラギン 上流と下流の製品情報
原材料
準備製品