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L-leucine is an essential amino acid. It is an enantiomer with D-leucine, odorless and slightly bitter. In the presence of hydrocarbons, it is stable in inorganic acid aqueous solution. It is slightly soluble in ethanol (0.07%), soluble in dilute hydrochloric acid and alkaline hydroxide and carbonate solutions.
1. L-leucine is a nutritional supplement, which is used to prepare amino acid infusion and comprehensive amino acid preparation, hypoglycemic agent and plant growth promoter. According to GB 2760-86, this product can be used as perfume.
2. L-leucine is used as amino acid infusion and comprehensive amino acid preparation. It is used for the diagnosis and treatment of idiopathic hyperglycemia in children. It is also suitable for liver disease, anemia, poisoning, muscular atrophy, polio sequelae, neuritis and psychosis with glucose metabolism disorders and reduced bile secretion.
The manufacture of amino acids began in 1820 when protein was hydrolyzed. The extraction sequence is L-cystine, L-histidine, L-leucine, L-arginine. In 1908, Japanese Ikeda found that sodium glutamate is a flavor enhancer, starting the history of industrial production of amino acids. In 1957, Japan began to use microorganisms for glutamic acid fermentation, which opened a new chapter in the history of amino acid production by microbial fermentation. Around the 1960s, the biosynthesis of L-leucine and its metabolic regulation mechanism were clarified successively. This provides a theoretical basis for the directed breeding of L-leucine production by microbial fermentation and the enzymatic production of L-leucine.
The production methods of L-leucine mainly include extraction, chemical synthesis, enzyme catalysis, microbial fermentation, etc.
Extraction method (protein hydrolysis method): Amino acid is the constituent unit of protein. Under acidic conditions, the protein with high content of L-leucine is hydrolyzed to obtain a mixture of various amino acids. L-leucine products are obtained through separation, purification, refinement and other processes.
Chemical synthesis method: Although the chemical synthesis method is simple in principle and low in price, the operation is complex, the reaction conditions are harsh, there are many products, the yield is not high, and some methods involve toxic substances. Leucine obtained by chemical synthesis is racemic DL-leucine. In order to obtain L-leucine, optical isomer resolution must be carried out.
Enzyme-catalyzed production: L-leucine is usually transferred by transaminase. L-leucine is generated from 1-keto-isohexanoic acid. The relevant enzymes and NADH are covalently bound on the membrane, and the substrate is slowly passed through the membrane to carry out enzyme-catalyzed reaction to produce L-leucine. For example, whether 1981 can be removed and the effect of removal. The most effective way to obtain mutants that accumulate target products is to release the normal metabolic control of microorganisms through gene mutation. Several common methods to obtain mutants are as follows: selecting and breeding nutrient deficient strains, cutting off or changing parallel metabolic pathways; Breeding mutants resistant to structural analogues to relieve feedback inhibition and repression; The mutant of cell membrane permeability was selected to make the target product secrete outside the cell, so that the concentration of the end product in the cell could not reach the concentration that caused feedback regulation; By means of genetic engineering and metabolic engineering, the microbial strains were purposely modified to synthesize the target products at high concentrations.
Natural products exist in the spleen, heart, etc., and in various animal and plant tissues in the form of protein. They can be dissociated after decomposition.
L-leucine is an essential amino acid. It is an enantiomer with D-leucine, odorless and slightly bitter. In the presence of hydrocarbons, it is stable in inorganic acid aqueous solution. It is slightly soluble in ethanol (0.07%), soluble in dilute hydrochloric acid and alkaline hydroxide and carbonate solutions.
1. L-leucine is a nutritional supplement, which is used to prepare amino acid infusion and comprehensive amino acid preparation, hypoglycemic agent and plant growth promoter. According to GB 2760-86, this product can be used as perfume.
2. L-leucine is used as amino acid infusion and comprehensive amino acid preparation. It is used for the diagnosis and treatment of idiopathic hyperglycemia in children. It is also suitable for liver disease, anemia, poisoning, muscular atrophy, polio sequelae, neuritis and psychosis with glucose metabolism disorders and reduced bile secretion.
The manufacture of amino acids began in 1820 when protein was hydrolyzed. The extraction sequence is L-cystine, L-histidine, L-leucine, L-arginine. In 1908, Japanese Ikeda found that sodium glutamate is a flavor enhancer, starting the history of industrial production of amino acids. In 1957, Japan began to use microorganisms for glutamic acid fermentation, which opened a new chapter in the history of amino acid production by microbial fermentation. Around the 1960s, the biosynthesis of L-leucine and its metabolic regulation mechanism were clarified successively. This provides a theoretical basis for the directed breeding of L-leucine production by microbial fermentation and the enzymatic production of L-leucine.
The production methods of L-leucine mainly include extraction, chemical synthesis, enzyme catalysis, microbial fermentation, etc.
Extraction method (protein hydrolysis method): Amino acid is the constituent unit of protein. Under acidic conditions, the protein with high content of L-leucine is hydrolyzed to obtain a mixture of various amino acids. L-leucine products are obtained through separation, purification, refinement and other processes.
Chemical synthesis method: Although the chemical synthesis method is simple in principle and low in price, the operation is complex, the reaction conditions are harsh, there are many products, the yield is not high, and some methods involve toxic substances. Leucine obtained by chemical synthesis is racemic DL-leucine. In order to obtain L-leucine, optical isomer resolution must be carried out.
Enzyme-catalyzed production: L-leucine is usually transferred by transaminase. L-leucine is generated from 1-keto-isohexanoic acid. The relevant enzymes and NADH are covalently bound on the membrane, and the substrate is slowly passed through the membrane to carry out enzyme-catalyzed reaction to produce L-leucine. For example, whether 1981 can be removed and the effect of removal. The most effective way to obtain mutants that accumulate target products is to release the normal metabolic control of microorganisms through gene mutation. Several common methods to obtain mutants are as follows: selecting and breeding nutrient deficient strains, cutting off or changing parallel metabolic pathways; Breeding mutants resistant to structural analogues to relieve feedback inhibition and repression; The mutant of cell membrane permeability was selected to make the target product secrete outside the cell, so that the concentration of the end product in the cell could not reach the concentration that caused feedback regulation; By means of genetic engineering and metabolic engineering, the microbial strains were purposely modified to synthesize the target products at high concentrations.
Natural products exist in the spleen, heart, etc., and in various animal and plant tissues in the form of protein. They can be dissociated after decomposition.
