L-メチオニン 化學特性,用途語,生産方法
外観
白色, 結晶～結晶性粉末
定義
本品は、次の化學式で表されるアミノ酸である。
溶解性
水100gに3g (0℃), 5.6g (30℃)溶解。有機溶媒に不溶。酸, アルカリ溶液に可溶。水にやや溶けやすく、エタノールに極めて溶けにくく、ジエチルエーテルにほとんど溶けない。塩酸又は水酸化ナトリウム溶液に溶ける。
解説
L-メチオニン，(S)-2-amino-4-(methylthio)butanoic acid．C5H11NO2S(149.21)．CH3SCH2CH2CH(NH2)COOH．略稱MetまたはM．必須アミノ酸の一つで，量的には少ないが分布は広い．発酵法で得られるホモセリンから工業(yè)的に合成できる．また，D,L-體はβ-メチルチオアセトアルデヒドからストレッカー法で合成される．生體中でメチル基の供與體として重要であり，ほかのアミノ酸の前駆物質である．六角板狀結晶．分解點280～281 ℃．[α]25D－8.2°(水)．pK1 2.15，pK2 9.06(25 ℃)．水に可溶，エタノール，エーテルに不溶．特異な臭気とわずかに甘みと苦みを有する．栄養(yǎng)剤，醫(yī)薬として用いる．LD50 29 mmol/kg(ラット，腹腔內)
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
効能
解毒薬
説明
Colorless or white lustrous plates, or a white crystalline powder.
It has a slight, characteristic odor. It is soluble in water, in alkali
solutions, and in dilute mineral acids. It is slightly soluble in
alcohol and practically insoluble in ether.
使用
L-Methionine is used as an essential amino acid for human development and therapeutically acts as an antidote for acetaminophen poisoning. It serves as a chelating agent for heavy metals, as a flavoring agent and nutritional supplement for foods. It acts as a feed additive, vegetable oil enrichment and as a single cell protein. In addition to this, it is used as a hepatoprotectant and also acts as a lipotropic agent and prevents excess fat buildup in the liver.
調製方法
Numerous methods have been described for manufacture of
methionine, including hydrolysis of methionine amide )and 5-(bmethylmercaptoethyl)-
hydantoin.
製造方法
The production method of choice for L-methionine is still the enzymatic resolution of racemic N-acetyl-methionine using acylase from Aspergillus oryzae. The production is carried out in a continuously operated fixed-bed or enzyme membrane reactor.
定義
ChEBI: L-methionine is the L-enantiomer of methionine. It has a role as a nutraceutical, a micronutrient, an antidote to paracetamol poisoning, a human metabolite and a mouse metabolite. It is an aspartate family amino acid, a proteinogenic amino acid, a methionine and a L-alpha-amino acid. It is a conjugate base of a L-methioninium. It is a conjugate acid of a L-methioninate. It is an enantiomer of a D-methionine. It is a tautomer of a L-methionine zwitterion.
一般的な説明
Minute hexagonal plates from dilute alcohol.
空気と水の反応
Reacts with water, steam, and/or acids to produce toxic and flammable vapors of hydrogen sulfide . Water soluble . pH of 1% aqueous solution is 5.6-6.0.
反応プロフィール
An organosulfide and amine derivative, carboxylic acid. Look at Reactive Groups 20 (organosulfides), 7 (amines), and 3 (carboxylic acids) may give indications about reactive tendencies. L-Methionine is an amino acid essential in human nutrition.
健康ハザード
ACUTE/CHRONIC HAZARDS: L-Methionine is dangerous when heated to decomposition; it emits dangerous and highly toxic fumes.
火災危険
Flash point data for L-Methionine is not available, but L-Methionine is probably combustible.
応用例（製薬）
Methionine is used in oral pharmaceutical formulations as a
flavoring agent.It has been included in parenteral formulations as
a pH controlling agent,and it has also been used experimentally
as an antioxidant with antibodies.Methionine is also used
therapeutically in oral tablets
安全性プロファイル
Mildly toxic by
ingestion and intraperitoneal routes. Human
mutation data reported. An experimental
teratogen. Experimental reproductive
effects. An essential sulfur-containing amino
acid. When heated to decomposition it emits
very toxic fumes of NOx and SOx.
安全性
Methionine is used in oral pharmaceutical formulations. The pure
form of methionine is mildly toxic by ingestion and by the IP route.
LD
50 (rat, IP): 4.328 g/k
LD
50 (rat, oral): 36 g/kg
概要
必須アミノ酸の一種．筋肉収縮に必要なエネルギー源としてのホスホクレアチニンの前駆體．生體內でのメチル基転位反応に関與し，生體內でシステインの前駆體としても重要．特異な臭気
貯蔵
Methionine is sensitive to light and should be stored in a cool, dark
place.
純化方法
Crystallise L-methionine from aqueous EtOH. Also purify it by dissolving ~0.5g of amino acid in ~10mL of hot H2O, filtering, adjusting the pH to 5.8 with 5N HCl, collecting the solid after addition of ~20mL of EtOH. It is recrystallised by dissolving in H2O and adding EtOH. It sublimes at 197-208o/0.3mm with 99.8% recovery and unracemised [Gross & Gradsky J Am Chem Soc 77 1678 1955]. [Milne & Peng J Am Chem Soc 79 647 1957, Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 pp 2125-2152 1961, Beilstein 4 IV 3189.]
不和合性
Methionine is incompatible with strong oxidizing agents.
規(guī)制狀況(Regulatory Status)
Included in the FDA Inactive Ingredients Database (oral tablets).
Included in parenteral preparations (injection solutions; powders
for reconstitution) licensed in the UK.
L-メチオニン 上流と下流の製品情報
原材料
準備製品