L-Methionine is an amino acid, white or slightly yellow crystalline powder, easily soluble in water, slightly soluble in ethanol and ether, insoluble in chloroform and benzene. L-methionine is an essential amino acid and plays an important role in human health. It is one of the components of protein, and also the substrate and cofactor of many important metabolic reactions in organisms.
The various uses of L-Methionine include:
1. Feed additive: L-methionine is an essential amino acid, which can be used as a feed additive in animal feed to promote the growth and development of animals.
2. Pharmaceutical field: L-methionine can be used to synthesize drugs, such as anti-tumor drugs and antiviral drugs.
3. Food additive: L-methionine can be used to enhance the nutritional value of food, such as added to infant formula food, nutrition and health care products and food for special medical purposes.
4. Cosmetics: L-methionine can be used in cosmetics. For example, it can be added to skin care products with whitening, antioxidant and moisturizing effects.
5. Chromatographic analysis: L-methionine can be used in chromatographic analysis as a reference material for chiral analysis and identification.
6. Industrial application: L-methionine can be used for industrial synthesis of methionine, ethionine and other compounds, as an intermediate in organic synthesis.
7. In a word, L-methionine has been widely used in many fields and has important economic and social significance.
L-Methionine is mainly produced by microbial fermentation. The specific steps are as follows:
1. Microbial screening: select microbial strains that can efficiently produce L-methionine, such as Escherichia coli, actinomycetes, etc.
2. Fermentation production: The selected microbial strains are cultured in a medium containing high-quality nitrogen and carbon sources, and after continuous fermentation and extraction, L-methionine fermentation broth with high concentration is obtained.
3. Refining and purification: The fermentation broth is separated and purified by a variety of separation technologies, such as ion exchange, gel filtration, countercurrent chromatography, etc., and finally high-purity L-methionine is obtained.
This microbial fermentation method is the main method for the industrial production of L-methionine at present. It has the advantages of high efficiency, sustainability and low cost. At the same time, there are other industrial synthesis methods, such as amino acid synthesis, amino acid conversion and other methods, but compared with microbial fermentation, these methods have higher production costs, so the degree of industrialization is low.
The reaction properties of L-Methionine are as follows:
1. Amino reaction: The amino group of L-methionine can react with acid or anhydride to form peptide bond or cyclic lactam bond.
2. Carboxyl reaction: The carboxyl group of L-methionine can react with amine or alcohol to form amide or ester.
3. Oxidation reaction: The side chain of L-methionine contains sulfur atoms, which is easy to be oxidized to disulfide, and can also be oxidized to sulfate or thioacid.
4. Reduction reaction: The side chain of L-methionine contains sulfur atoms, which can be reduced to mercapto or mercaptan.
5. Phosphorylation reaction: the hydroxyl of L-methionine can be phosphorylated into phosphate, for example, methylthiomethionine can be phosphorylated into methylthiomethionine phosphate, etc.
6. Acetal reaction: L-methionine can react with carbonyl compounds to form acetal products with two carbon atoms.
7. Methylation reaction: the sulfur atom of L-methionine can be methylated to form methylthiomethionine and other products.
In short, L-methionine has rich reaction properties and can take place in many different reactions. These reactions play an important role in the application and research of L-methionine.
The discovery history of L-Methionine can be traced back to the end of the 19th century.
In 1902, Frederick Gowland Hopkins, a British biochemist, found that animals need certain nutrients to grow and develop normally. He called these nutrients "growth factors", one of which is the amino acid in protein.
In 1913, Vincent du Vigneaud, an American biochemist, discovered that L-methionine is an amino acid containing sulfur and can be isolated from bird protein. He also found that L-methionine is an essential amino acid and plays an important role in animal growth and development.
At the beginning of the 20th century, scientists began to study the structure and function of amino acids, and L-methionine gradually became one of the focuses of research. At present, L-methionine has become one of the basic knowledge in the field of nutrition and biochemistry, and is of great significance to the growth, development and health of human and animals.