L-Methionin

Gefahreninformationscode (GHS)

• Bildanzeige (GHS)

  

• Alarmwort

  Warnung

• Gefahrenhinweise

  H302：Gesundheitsschädlich bei Verschlucken.

• Sicherheit

  P264：Nach Gebrauch gründlich waschen.

  P264：Nach Gebrauch gründlich waschen.

  P270：Bei Gebrauch nicht essen, trinken oder rauchen.

L-Methionine Chemische Eigenschaften,Einsatz,Produktion Methoden

• R-Sätze Betriebsanweisung:

  R33:Gefahr kumulativer Wirkungen.

• S-Sätze Betriebsanweisung:

  S24/25:Berührung mit den Augen und der Haut vermeiden.

• Beschreibung

  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.

• Chemische Eigenschaften

  Methionine occurs as a white or almost white, crystalline powder or colorless crystals.

• Chemische Eigenschaften

  White crystalline powder

• Originator

  Meonine ,Ives,US,1944

• Verwenden

  methionine is slows down and normalizes oil gland sebum production. Methionine is also used as a texturizer in cosmetic creams. It is an essential amino acid found in a number of proteins and obtained by means of fermentation.

• Verwenden

  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.

• Verwenden

  Essential aminoacid for human development. Hepatoprotectant; antidote (acetominophen poisoning); urinary acidifier.

• synthetische

  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.

• Definition

  ChEBI: The L-enantiomer of methionine.

• Vorbereitung Methode

  Numerous methods have been described for manufacture of methionine, including hydrolysis of methionine amide )and 5-(bmethylmercaptoethyl)- hydantoin.

• Manufacturing Process

  A 3-necked flask fitted with a stirrer, thermometer, gas inlet, dropping funnel, and brine-cooled reflux condenser was charged with 53 g (1.1 mol) methyl mercaptan and 0.35 g mercuric methyl mercaptide. After admitting 56 g (1.0mol) of acrolein during the course of 15 minutes with an inside temperature of about 10°C, the temperature was allowed to rise spontaneously to 75°C, at which point an ice bath was applied. There was no indication of further reaction one hour after the addition of the acrolein. Distillation of the product gave 71 g (yield 68%) of β-methylmercaptopropionaldehyde, as described in US Patent 2,584,496.
  Then as described in US Patent 2,732,400, β-methylmercaptopropionaldehyde (0.60 M) (56.5 g) is added to a stirred solution of sodium cyanide (0.66 M) (32.4 g) and ammonium chloride (0.63 M) (33.7 g) in water (140 ml). The temperature of the mixture rises to 49°C and is maintained at this point by heat evolution for about 5 minutes when it slowly begins to fall. Methanol (50 ml) is added and the mixture is stirred for 4 hours as the temperature falls to 28°C (room temperature).
  After chilling to +12°C, additional methanol (35 ml) and a concentrated aqueous ammoniun hydroxide solution (1.4 M) (100 ml) are added and stirring is continued for 2 hours at a temperature maintained at from +5° to +15°C. The organic layer is separated and solvent is stripped from the aqueous layer at water aspirator pressure at a temperature below 40°C. The residue is extracted several times with chloroform and the chloroform extracts are combined with the separated oil. Chloroform is removed at water aspirator pressure at a temperature below 35°C to leave crude α-amino-γmethylmercaptobutyronitrile (methionine nitrile) in 88% yield (68 g) as a clear, somewhat viscous oil.
  The methionine nitrile (20 g) is dissolved in a solution prepared from 50 ml of aqueous 5 N sodium hydroxide solution and 65 ml of ethanol. The solution is then refluxed for 24 hours; ammonia is evolved. The solution is treated with activated carbon, filtered, acidified with glacial acetic acid (17 ml), chilled to - 10°C and filtered to give crude product. This crude product is then slurried with a solution made up of 20 ml of water and 20 ml of methanol, filtered at - 5° to +10°C and dried to give dl-methionine as white platelets.

• Therapeutic Function

  Lipotropic

• Synthesis Reference(s)

  Canadian Journal of Chemistry, 47, p. 3271, 1969 DOI: 10.1139/v69-542
  Synthetic Communications, 26, p. 3619, 1996 DOI: 10.1080/00397919608003774

• Allgemeine Beschreibung

  Minute hexagonal plates from dilute alcohol.

• Air & Water Reaktionen

  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.

• Reaktivität anzeigen

  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.

• Health Hazard

  ACUTE/CHRONIC HAZARDS: L-Methionine is dangerous when heated to decomposition; it emits dangerous and highly toxic fumes.

• Brandgefahr

  Flash point data for L-Methionine is not available, but L-Methionine is probably combustible.

• Pharmazeutische Anwendungen

  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

• Biochem/physiol Actions

  L-Methionine serves as precursor for transmethylation and transsulphuration. Methionine adenosylation results in the formation of S-adenosyl-L-methionine (SAM). SAM serves as a methyl donor to a number of substances. This methylation is significantly associated with the immune system functioning. Thus, SAM deficiency causes severe combined immunodeficiencies. L-Methionine′s metabolic product, glutathione, is known to regulate immune response and has antiviral action.

• Sicherheitsprofil

  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.

• Sicherheit(Safety)

  Methionine is used in oral pharmaceutical formulations. The pure form of methionine is mildly toxic by ingestion and by the IP route.
  LD₅₀ (rat, IP): 4.328 g/k
  LD₅₀ (rat, oral): 36 g/kg

• Lager

  Methionine is sensitive to light and should be stored in a cool, dark place.

• läuterung methode

  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.]

• Inkompatibilitäten

  Methionine is incompatible with strong oxidizing agents.

• 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-Methionine Upstream-Materialien And Downstream Produkte

L-Methionin Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

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