L-Methionin

Bezeichnung:L-Methionin

CAS-Nr63-68-3

Englisch Name:L-Methionine

CBNumberCB9208759

SummenformelC5H11NO2S

Molgewicht149.21

MOL-Datei63-68-3.mol

Synonyma

L-Methionin

L-Methionin physikalisch-chemischer Eigenschaften

Schmelzpunkt	284 °C (dec.)(lit.)
alpha	23.25 º (c=2, 6N HCl)
Siedepunkt	393.91°C (estimate)
Dichte	1,34g/cm
chüttdichte	550kg/m3
Brechungsindex	1.5216 (estimate)
storage temp.	20-25°C
Löslichkeit	1 M HCl: 0.5 M at 20 °C, clear, colorless
Aggregatzustand	Solid
pka	2.13(at 25℃)
Farbe	White
Geruch (Odor)	Slight characteristic
PH	5-7 (10g/l, H2O, 20℃)
Optische Aktivität	[α]20/D +23.7±0.5°, c = 5% in 5 M HCl
Biologische Quelle	synthetic
Wasserlöslichkeit	Soluble
maximale Wellenlänge (λmax)	λ: 260 nm Amax: 0.40 λ: 280 nm Amax: 0.05
Merck	14,5975
BRN	1722294
Stabilität	Stable. Incompatible with strong oxidizing agents.
LogP	0.217 (est)
CAS Datenbank	63-68-3(CAS DataBase Reference)
NIST chemische Informationen	L-Methionine(63-68-3)
EPA chemische Informationen	L-Methionine (63-68-3)

Sicherheit

R-Sätze:	33
S-Sätze:	24/25
WGK Germany	2
RTECS-Nr.	PD0457000
F	10-23
TSCA	Yes
HS Code	29304010
Giftige Stoffe Daten	63-68-3(Hazardous Substances Data)
Toxizität	LD50 oral in rat: 36gm/kg

Gefahreninformationscode (GHS)

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.
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.
Definition
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.
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.
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.

63-68-3, L-Methionine Verwandte Suche:

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