ChemicalBook >> CAS DataBase List >>DL-Methionine


Chemical Name:
Molecular Formula:
Molecular Weight:
MDL Number:
MOL File:
MSDS File:

DL-Methionine Properties

Melting point 284 °C (dec.)(lit.)
alpha -1~+1°(D/20℃)(c=8,HCl)
Boiling point 306.9±37.0 °C(Predicted)
Density 1.34
refractive index 1.5216 (estimate)
storage temp. 2-8°C
solubility 1 M HCl: 0.5 M at 20 °C, clear, colorless
pka 2.13(at 25℃)
form Crystals or Crystalline Powder
color White
optical activity [α]/D, c = 5 in 5 M HCl (inactive)
Water Solubility 2.9 g/100 mL (20 ºC)
Merck 14,5975
JECFA Number 1424
BRN 636185
Stability Stable. Incompatible with strong oxidising agents.
CAS DataBase Reference 59-51-8(CAS DataBase Reference)
Substances Added to Food (formerly EAFUS) DL-METHIONINE
FDA 21 CFR 310.545
NIST Chemistry Reference Methionine(59-51-8)
EPA Substance Registry System Methionine (59-51-8)


Risk and Safety Statements

Hazard Codes  Xi
Risk Statements  33-36/37/38
Safety Statements  24/25-36-26
WGK Germany  2
RTECS  PD0457000
HS Code  29304090
NFPA 704
1 0

DL-Methionine price More Price(57)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich PHR2653 Racemethionine Pharmaceutical Secondary Standard; Certified Reference Material 59-51-8 500MG $233 2022-05-15 Buy
Sigma-Aldrich 64340 DL-Methionine ≥99.0% (NT) 59-51-8 1kg $160 2022-05-15 Buy
Sigma-Aldrich 1643292 Racemethionine United States Pharmacopeia (USP) Reference Standard 59-51-8 200mg $434 2022-05-15 Buy
TCI Chemical M0463 DL-Methionine >99.0%(HPLC)(T) 59-51-8 25g $16 2022-04-27 Buy
TCI Chemical M0463 DL-Methionine >99.0%(HPLC)(T) 59-51-8 500g $91 2022-04-27 Buy
Product number Packaging Price Buy
PHR2653 500MG $233 Buy
64340 1kg $160 Buy
1643292 200mg $434 Buy
M0463 25g $16 Buy
M0463 500g $91 Buy

DL-Methionine Chemical Properties,Uses,Production


Methionine (2-amino-4(methylthio)-butanoic acid) is one of the essential amino acids, which are used by our bodies to make proteins and can only be supplied by diets. Methionine is found in metal, fish, and dairy products, and it plays an important role in many cell functions.
With an asymmetric carbon, methionine molecules can be D (Dextrogyre) or L (Levogyre), optical isomers. L-methionine is the biologically active form of methionine in proteins. D-methionine is converted into L-methionine by enzymatic processes inside animal bodies in such a way that L- and D-methionine are equivalent for animal nutrition. D,L-methionine (DLM) is the most common form of commercialized methionine, composed of the racemic mixture of D and L-methionine.  D,L-methionine is commercialized as a white crystalline powder, containing 99% of active substance, or in a brown liquid form with 40% purity, made from the dissolution of D,L-methionine in sodium hydroxide.
Methionine is used to prevent liver damage in acetaminophen (Tylenol) poisoning. It is also used to increase the acidity of urine, to treat liver disorders, and to improve wound healing. Furthermore, it is used for the treatment of depression, alcoholism, allergies, asthma, copper poisoning, radiation side effects, schizophrenia, drug withdrawal, and Parkinson's disease. Methionine is registered as an ingredient for use in cosmetics as antistatic and for skin conditioning (Commission Decision 2006/257/EC).
D,L-methionine is used in animal feeds for poultry and pigs, as well as in diets for cats and dogs. D,L-methionine technically pure protected with copolymer vinylpyridine/styrene, and D,L-methionine protected with ethylcellulose when used as a feed additive for ruminants, are currently authorized for use for all animal species and ruminants, respectively, by Regulation (EU) No 469/2013.


[1] DL-Methionine from Methional and Hyddrogen Cyanide – Cost Analysis – Methionine E11A (2016)


Methionine is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CH2SCH3. This essential amino acid is classified as nonpolar. This amino-acid is coded by the initiation codon AUG which indicates mRNA's coding region where translation into protein begins.

Chemical Properties

d,l-Methionine has a characteristic odor. It is an essential amino acid and is also used as a nutrient and dietary supplement.

Chemical Properties

White, crystalline platelets or powder having a characteristic odor. One g dissolves in about 30 mL of water. It is soluble in dilute acids and in solutions of alkali hydroxides. It is very slightly soluble in alcohol, and practically insoluble in ether. It is optically inactive. The pH of a 1 in 100 solution is between 5.6 and 6.1. This substance may be prepared by addition of methanethiol to acrolein; by chemical conversion of methylthiopropionic aldehyde.

Chemical Properties

White crystalline powder


High levels of methionine can be found in eggs, sesame seeds, Brazil nuts, fish, meats and some other plant seeds; methionine is also found in cereal grains. Most fruits and vegetables contain very little of it. Most legumes are also low in methionine. Racemic methionine is sometimes added as an ingredient to pet foods.


DL-Methionine is sometimes given as a supplement to dogs; it helps keep dogs from damaging grass by reducing the pH of the urine.
Methionine is allowed as a supplement to organic poultry feed under the US certified organic program.


Production of volatile compounds related to the flavour of foods from the Strecker degradation of DL-methionine. Addition of methionine in appropriate amounts to these foods might be expected to improve protein value. Economically, DL-methionine would be preferable.


An essential nonpolar amino acid with oxidative stress defense properties


By addition of methanethiol to acrolein; by chemical conversion of methylthiopropionic aldehyde.


ChEBI: A sulfur-containing amino acid that is butyric acid bearing an amino substituent at position 2 and a methylthio substituent at position 4.

brand name

Pedameth (Forest).


As an essential amino acid, methionine is not synthesized de novo in humans, who must ingest methionine or methioninecontaining proteins. In plants and microorganisms, methionine is synthesized via a pathway that uses both aspartic acid and cysteine. First, aspartic acid is converted via β-aspartyl-semialdehyde into homoserine, introducing the pair of contiguous methylene groups. Homoserine converts to O-succinyl homoserine, which then reacts with cysteine to produce cystathionine, which is cleaved to yield homocysteine. Subsequent methylation of the thiol group by folates affords methionine. Both cystathionine-γ-synthase and cystathionine- β-lyase require pyridoxyl-5′-phosphate as a cofactor, whereas homocysteine methyltransferase requires vitamin B12 as a cofactor.

Biotechnological Production

DL-Methionine is the second amino acid that is almost exclusively manufactured by chemical synthesis. The process used today was originally developed by Werner Schwarze at Degussa in the 1940s, and has been continually improved and refined since. Today DL-methionine is manufactured in several plants, each with a capacity of more than 100,000 tonnes. To operate the process on an industrial scale also requires back-integration into the key hazardous raw materials acrolein, methyl mercaptan, and hydrogen cyanide. After the formation of the hydantoin, the key step is alkaline hydrolysis of the hydantoin, to produce methionine directly in up to 95 % yield based on acrolein.

Biological Functions

Together with cysteine, methionine is one of two sulfurcontaining proteinogenic amino acids. Its derivative S-adenosyl methionine (SAM) serves as a methyl donor. Methionine is an intermediate in the biosynthesis of cysteine, carnitine, taurine, lecithin, phosphatidylcholine, and other phospholipids. Improper conversion of methionine can lead to atherosclerosis.
This amino acid is also used by plants for synthesis of ethylene. The process is known as the Yang Cycle or the methionine cycle.
Methionine is one of only two amino acids encoded by a single codon (AUG) in the standard genetic code (tryptophan, encoded by UGG, is the other). The codon AUG is also the most common eukaryote "Start" message for a ribosome that signals the initiation of protein translation from mRNA when the AUG codon is in a Kozak consensus sequence. As a consequence, methionine is often incorporated into the N-terminal position of proteins in eukaryotes and archaea during translation, although it can be removed by post-translational modification. In bacteria, the derivative Nformylmethionine is used as the initial amino acid.

General Description

DL-Methionine is an essential amino acid containing sulphur. Methionine consists of an asymmetric carbon and exists as D (dextrogyre) and L (levogyre) optical isomers. The L-methionine is considered as biologically active. The racemic mixture of D and L-isomers forms DL-methionine, which is the commercially available methionine.

Biochem/physiol Actions

Methionine offers protection against disorders related to hair, skin and nails. It elevates lecithin production in the liver and thereby reduces cholesterol level. It naturally serves as a heavy metal chelating agent, regulating ammonia concentration in the urine. This ameliorates bladder irritation. Methionine is also known to induce hair growth.

Safety Profile

Moderately toxic by ingestion and other routes. An experimental teratogen. Experimental reproductive effects. When heated to decomposition it emits toxic fumes of SOx and NOx. See also 1-METHIONINE.

Purification Methods

Crystallise it from hot water or EtOH. Also purify it by dissolving it in H2O and passing through an Amberlite IR-120 resin (NH4+ form). The eluate is concentrated and then passed through Amberlite IR-4B resin, and this eluate is evaporated to dryness. The residue is washed with EtOH, then Me2CO, dried and recrystallised from aqueous EtOH (colourless plates) [Baddiley & Jamieson J Chem Soc 4283 1954]. [Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 p 2125 1961, Beilstein 4 IV 3190.]

Other biochemical pathways

Although mammals cannot synthesize methionine, they can still use it in a variety of biochemical pathways:
Generation of homocysteine Methionine is converted to S-adenosyl methionine (SAM) by (1) methionine adenosyltransferase.
SAM serves as a methyl-donor in many (2) methyl transferase reactions, and is converted to S-adenosylhomocysteine (SAH).
(3) Adenosyl homocysteinase converts SAH to homocysteine.
There are two fates of homocysteine: it can be used to regenerate methionine, or to form cysteine.
Regeneration of methionine
Methionine can be regenerated from homocysteine via methionine synthase in a reaction that requires Vitamin B12 as a cofactor.
Homocysteine can also be remethylated using glycine betaine (NNN-trimethyl glycine, TMG) to methionine via the enzyme betainehomocysteine methyltransferase (E.C., BHMT). BHMT makes up to 1.5% of all the soluble protein of the liver, and recent evidence suggests that it may have a greater influence on methionine and homocysteine homeostasis than methionine synthase.

DL-Methionine Preparation Products And Raw materials

Global( 820)Suppliers
Supplier Tel Email Country ProdList Advantage
Frapp's ChemicalNFTZ Co., Ltd.
+86 (576) 8169-6106 China 886 50
Capot Chemical Co.,Ltd.
571-85586718 +8613336195806 China 19995 60
Henan DaKen Chemical CO.,LTD.
+86-371-66670886 China 16704 58
Henan Tianfu Chemical Co.,Ltd.
+86-0371-55170693 +86-19937530512 China 22021 55
Shanghai Time Chemicals CO., Ltd.
+86-021-57951555 +8617317452075 China 1809 55
Shanghai Yingrui Biopharma Co., Ltd.
+86-21-33585366 CHINA 739 60
21-51619050 China 30644 60
Hefei TNJ Chemical Industry Co.,Ltd.
0551-65418679 China 2995 55
Shanghai Zheyan Biotech Co., Ltd.
18017610038 CHINA 3623 58
career henan chemical co
+86-0371-86658258 China 29960 58

View Lastest Price from DL-Methionine manufacturers

Image Update time Product Price Min. Order Purity Supply Ability Manufacturer
2022-07-22 DL-Methionine
US $0.20 / g 10g 99% 300tons Hebei Dangtong Import and export Co LTD
2022-03-19 DL-Methionine
US $4.00 / kg 1kg 99% 200mt Jinan Finer Chemical Co., Ltd
2022-03-17 DL-Methionine
US $25.00-22.00 / kg 1kg 99% 20 tons XI'AN TIANGUANGYUAN BIOTECH CO., LTD.
  • DL-Methionine
  • US $0.20 / g
  • 99%
  • Hebei Dangtong Import and export Co LTD
  • DL-Methionine
  • US $4.00 / kg
  • 99%
  • Jinan Finer Chemical Co., Ltd
  • DL-Methionine
  • US $25.00-22.00 / kg
  • 99%
DL-Methionine≥ 99% (Titration) (RS)-Methionine Kochia fruit extract (10:1) DL-Met-OH DL-METHIONINE (13C5,D8,15N) DL-METHIONINE (METHYL-13C) Kochia seed extract BUFFER SOLUTION PH 4 AVS TITRINORM BOM BUFFER PH10 (20°C) AVS TITRINORM DL-Methionine Vetec(TM) reagent grade, 98% DL-Methionine(F DL-Methionine、AciMeti (n)-2-amino-4-(methylthio)butyric acid DL-Methionine,99% (S)-2-AMINO-4-(METHYLMERCAPTO)BUTYRIC ACID (S)-(+)-METHIONINE 2-AMINO-4(METHYLTHIO)BUTYRIC ACID 2-AMINO-4-METHYLMERCAPTOBUTYRIC ACID AKOS AUF2097 acimetion DL- MATHIONINE DL-METHIONINE FEED GRADE / POULTRY DL-Methoionine (+/-)-2-Amino-4-(methylthio)butyric acid~H-DL-Met-OH DL-METHIONINE FOR BIOCHEMISTRY Dl-MethionineForBiochemistry99+% DL-LETHIONINE DL-Methionine FCC DL-METHIONINE 98.5+% FCC DL-METHIONINE CELL CULTURE TESTED L-2-AMINO-4-(METHYLTHIO)BUTANOIC ACID L-2-AMINO-4-METHYLMERCAPTOBUTYRIC ACID Metion -Methylmercapto-aminobutyricacid Methionine dl-form Methionine (NF XIV) Methilonin Methilanin Mertionin Meonine (R,S)-2-Amino-4-methylsulfanyl-butyricacid (RS)-2-Amino-3-methylthiobutansαure Metione Neston Pedameth Petameth α-amino-γ-methylmercaptobutyricacid FEMA 3301 DL-2-AMINO-4-METHYLTHIOBUTANOIC ACID DL-2-AMINO-4-(METHYLTHIO)BUTYRIC ACID DL-BANTHIONINE DL-LOBAMINE DL-METHIONINE METHIONINE, L- METHIONINE, DL- L-LOBAMINE L-BANTHIONINE ACETYL-DL-METHIONINE, N-(P)