CAS number：59-51-8
molecular formula：C5H11NO2S
molecular weight：149.21
EINECS number：200-432-1

English synonyms

(R,S)-2-Amino-4-methylsulfanyl-butyricacid;(RS)-2-Amino-3-methylthiobutansαure;Metione;Neston;Pedameth;Petameth;Thiomedon;Urimeth

Related categories

Amino acids; intermediates; common amino acids and protein drugs; biochemical engineering; other biochemical reagents; pharmaceutical intermediates; protected amino acids; unnatural amino acids; standard products and standard substances; organic chemistry; pharmaceutical raw materials; amino acid infusion raw materials; nutritional agents; Food and Feed Additives; Biochemicals; Chemical Reagents; Raw Materials; Nutritional Enhancers; Raw Materials; Raw Material Intermediates-APIs; Nutritional Enhancers-Amino Acids; and derivatives; amino acid additives; feed additives; amino acids; food additives; nutritional supplements (nutritional supplements; amino acids and their derivatives; amino acid pharmaceutical intermediates; standard products; biochemical reagents; plant extracts; biochemical reagents - amino acids; Chemical products-organic chemicals; proportional extracts; food additives; chemical raw materials-1; organic raw materials; PCR kits-probe method fluorescent quantitative PCR kits; medical raw materials; raw materials; standard products-traditional Chinese medicine standard products; biochemical reagents-amino acids ;Food Additions;Standard Substances, Reference Substances;Medicine, Pesticide and Dye Intermediates;Reference Substances;APIs;Chemical Materials;Chinese Medicine Reference Substances;DL-Amino Acids;Proportional Extracts;Chemicals;Amino Acids;Amino Acid Derivatives;Methionine [ Met, M];Amino Acids;feed additives;chemical products;chemical raw materials;nutritional enhancers;organic chemical industry;general biochemical reagents-amino acids;PCR kits;kits-Elisa kits;chemical reagents;bc0001

Introduction

DL-methionine is white flake crystal or crystalline powder. Has a special smell. The taste is slightly sweet. The melting point is 281 degrees (decomposition). The pH value of 10% aqueous solution is 5.6-6.1. No optical activity. It is stable to heat and air. It is unstable to strong acid and can cause demethylation. Soluble in water (3.3g/100ml, 25 degrees), dilute acid and dilute solution. Extremely insoluble in ethanol, almost insoluble in ether.

Chemical properties

DL-methionine is white flake crystal or crystalline powder. Has a special smell. The taste is slightly sweet. The melting point is 281 degrees (decomposition). The pH value of 10% aqueous solution is 5.6-6.1. No optical activity. It is stable to heat and air. It is unstable to strong acid and can cause demethylation. Soluble in water (3.3g/100ml, 25 degrees), dilute acid and dilute solution. Extremely insoluble in ethanol, almost insoluble in ether.

Use

●  DL-methionine can be used as a nutritional supplement. It has the same physiological effect as L-methionine, but the price is low (L-type is produced from DL-type), so DL-methionine is generally used. In oats, rye, rice, corn, wheat, peanut flour, soybeans, potatoes, spinach and other plant foods to improve amino acid balance.

●  It is suitable for the prevention and treatment of liver disease and arsenic or benzene poisoning, and it can also be used for the treatment of malnutrition caused by protein deficiency after dysentery and chronic infectious diseases

●  This product is a feed nutrition enhancer. The lack of methionine in livestock and poultry will cause stunting, weight loss, weakened liver and kidney functions, muscle atrophy, and fur deterioration. Adding 1kg of methionine to the feed is equivalent to the nutritional value of 50kg of fish meal. The general adding amount in the feed is 0,05%-0.2%.

●  nutritional supplements. It has the same physiological effect as L-methionine, but the price is low (L-type is made from DL-type), so DL-methionine is generally used. It is a limiting amino acid in plant foods such as oats, rye, rice, corn, wheat, peanut flour, soybeans, potatoes, and spinach. Add to the above foods to improve amino acid balance. Requirements vary with cystine intake. Adult men need 1.1g/d.
The sea urchin taste is related to methionine, the sweetness of sea urchin is related to glycine and alanine, the bitterness is related to valine, and the umami taste is related to glutamic acid, etc. Therefore, these amino acids can be formulated into flavoring agents.
It is still used in amino acid infusion and comprehensive amino acid preparations.
According to my country's GB 2760-86 regulations, it can be used as a spice.

●  The content of commercial methionine is ≥98.5%. It is one of the amino acids necessary for the growth of poultry and livestock animals. It is the "skeleton" amino acid for biosynthesizing proteins. It has a strong regulatory effect on the metabolism of animals and is widely used in medicine, food, feed and cosmetics. Among them, in medicine, it can be used as the main component of amino acid infusion and compound amino acid, and can also be used for the synthesis of medicinal vitamins. With its anti-fatty liver effect, it can be used to produce liver protection preparations; in food, it can be used for amino acid strengthening and The processing of food health products can be used as a nutritional supplement. Because of the special smell, it is only used in fish cake products; in the feed industry, methionine is used in the largest amount, and it is used as a nutritional enhancer for feed to make up for the balance of amino acids. Feed additives, in the variety of amino acid nutritional feed additives, methionine accounts for 60%, lysine accounts for 30%, and other amino acids account for about 10%.

●  used as biochemical reagent

●  Biochemical research; culture applications for mammalian and insect cells where mixed isoforms are labeled

Production method

●  The extraction method can be used to prepare methionine, but there are the following methods in industry: 1. Rhone-Planck process 2. Degussa DL-methionine process raw material consumption quota: acrolein 480kg/t, methyl mercaptan 400kg/t, cyanide Sodium chloride 420kg/t.

●  D-configuration and L-configuration of methionine have the same physiological function, and DL-form is mostly used, so it is advantageous to produce it by synthetic method. It is generally prepared by the reaction of acrolein and methyl mercaptan.

●  The synthesis method using acrolein as raw material is usually adopted.
Acrolein and methyl mercaptan are condensed in the presence of formic acid and copper acetate to produce 3-methylthiopropanal. Then mix with sodium cyanide and ammonium bicarbonate solution. The reaction at 90°C yields methylthioethylhydantoin. Without separation and purification, it can be heated to 180°C with 28% sodium hydroxide solution to hydrolyze to form sodium methionine. Neutralize with hydrochloric acid to obtain finished methionine. Each ton of product consumes 480kg of acrolein, 400kg of methyl mercaptan, and 420kg of sodium cyanide.

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