CAS number：52-90-4
molecular formula：C3H7NO2S
molecular weight：121.16
EINECS number：200-158-2
(R)-2-Amino-3-mercaptopropanoic acid;3-mercapto-l-alanin;alpha-amino-beta-mercaptopropionicacid;alpha-Amino-beta-thiolpropionic acid;alpha-amino-beta-thiolpropionicacid;Cystein;half-cysteine;L-Cysteine - animal origin
Plant extracts; chemical biology; standard products; amino acids; other biochemical reagents; pharmaceutical intermediates; isotope labels; intermediates; amino acids; antipyretic and analgesic APIs; And protein drugs; biochemical industry; protected amino acids; vitamins and amino acids; pharmaceutical raw materials; biochemical industry; raw materials; daily chemical raw materials/cosmetics; chemical reagents; ;L-amino acid; Dough quality improver; Food additive; Wheat flour, starch modifier; Amino acid and its derivatives; Biochemical reagents; Biochemicals; Microorganisms; Amino acid derivatives; Raw materials for food additives; Antioxidants; nutritional enhancers; biochemical reagents - amino acids; nutritional enhancers - amino acids; chemical raw materials - 1; raw materials; medical raw materials; Standard substances, reference substances; pharmaceutical, pesticide and dye intermediates; traditional Chinese medicine reference substances; L-amino acids; organic chemical raw materials; impurity reference substances; chemical raw materials; chemical industry; API intermediates; Amino Acids and Derivatives; alpha-Amino Acids; Antioxidant; Biochemistry; Nutritional Supplements; L-Amino Acids; Amino Acids; amino; organic intermediates; ; Nutrient solution for injection, amino acid; amino acid for nutrition enhancer; clinical test standard substance
L-cysteine, also known as cysteine, is a non-essential amino acid for the human body. Amino acid is the constituent unit of protein. Protein is the material basis of life. From humans to microorganisms, all are composed of proteins. Proteins are made up of peptides whose chains are made up of amino acids. Different proteins are composed of peptide chains with different sequences and lengths of amino acids. Genes related to heredity are actually chains of amino acids in different sequences.
| Melting point | 240 °C (dec.) (lit.) |
| Specific optical rotation | 8.75 º (c=12, 2N HCl) |
| Boiling point | 293.9±35.0 °C(Predicted) |
| Density | 1.197 (estimate) |
FEMA | 3263 | L-CYSTEINE |
| Refractive index | 8.8 ° (C=8, 1mol/L HCl) |
| Storage conditions | Store below +30°C. |
| Solubility | H2O: 25 mg/mL |
| Acidity coefficient(pKa) | 1.92(at 25℃) |
| Shape | Solid |
| Color | White |
| PH value | 4.5-5.5 (100g/l, H2O, 20℃) |
Optical activity | Optical rotation: +8° to +9° (c = 5, 1 N HCl, 20°C). |
| Water solubility | 280 g/L (25 ºC) |
| Sensitive | Air Sensitive |
| Maximum wavelength(λmax) | λ: 260 nm Amax: 1.5 |
JECFA Number | 1419 |
Merck | 14,2781 |
BRN | 1721408 |
| Stability | Stability Stable, but may be air sensitive. Incompatible with oxidizing agents, bases. |
| CAS database | 52-90-4(CAS DataBase Reference) |
Colorless to white fine columnar crystal or white crystalline powder, with slight special smell and taste (slightly sour). With reductive, anti-oxidant and prevent non-enzymatic browning effect. The melting point is 175°C (decomposition). Soluble in water, the aqueous solution is acidic, with a pH value of 1.2 at 3%, 1.7 at 1%, and 2.4 at 0.1%. Also soluble in ethanol, ammonia and acetic acid, insoluble in ether, acetone, benzene, carbon disulfide and chloroform.
One of the amino acids, but it is a non-essential amino acid.
● Bread Improver; Nutritional Supplement; Antioxidant; Color Protectant. It has a detoxification effect on acrylonitrile and aromatic acidosis; it has the effect of preventing radiation damage; it has the effect of treating bronchitis and reducing phlegm; it has the effect of absorbing alcohol and converting it into acetaldehyde in the body.
According to the provisions of GB 2760-96, it is allowed to be used in spices.
● It is used to treat eczema, urticaria, freckles and other skin diseases, and its series of products are widely used in the pharmaceutical, food and cosmetic industries
● It is used in biochemical research, and used as an antidote for hepatitis, liver poisoning, radioactive drug poisoning, antimony poisoning, etc. in medicine.
● Mainly used in medicine, cosmetics, biochemical research, etc. Used in bread materials to promote the formation of gluten and promote fermentation, mold release, and prevent aging. Used in natural fruit juices to prevent oxidation of vitamin C and prevent the juice from turning brown. The product has a detoxification effect and can be used for acrylonitrile poisoning and aromatic acid poisoning. This product also has the effect of preventing radiation damage to the human body, and it is also a drug for treating bronchitis, especially as an expectorant (mostly used in the form of acetyl L-cysteine methyl ester salt. Cosmetics are mainly used for beauty water, Hair perm lotion, sunscreen skin cream, etc.
● Widely used in medicine, food and cosmetics and other industries.
● Uses: Mainly used in medicine, cosmetics, biochemical research, etc. Used in bread materials to promote the formation of gluten and promote fermentation, mold release, and prevent aging. For the treatment of eczema, urticaria, freckles and other skin diseases.
● NMDA glutamate receptor agonists
● 1. Tin particle reduction method Dissolve cystine in dilute hydrochloric acid, filter, add tin particles to the filtrate and heat up to reflux for 2 hours. Dilute the reducing solution with water, remove the remaining tin particles, add hydrogen sulfide to make it saturated, filter, wash the filter residue with a small amount of water, combine the washing and filtrate, concentrate under reduced pressure, cool and crystallize, filter and dry to obtain L-cysteine salt salt. 2. Electrolytic reduction method Add distilled water, hydrochloric acid, and cystine to the electrolytic tank, stir and dissolve, and maintain the electrolysis at a temperature below 50°C until the end. The resulting electrolyte was passed through hydrogen sulfide for several hours and filtered. The filtrate was decolorized by adding activated carbon, concentrated under reduced pressure after filtration, crystallized by cooling, filtered, and dried to obtain L-cysteine hydrochloride.
● Obtained from L-cysteine hydrochloride as raw material, neutralized and refined by alkali
● Heating the hair (or animal hair, feather) with hydrochloric acid for 6-8 hours for hydrolysis, distilling the hydrochloric acid under reduced pressure, adding activated carbon for decolorization, filtering, and neutralizing the filtrate with ammonia to obtain coarse crystals of L-cystine, which are then used Ammonia solution is dissolved and neutralized, and after recrystallization, it is dissolved with hydrochloric acid and electrolytically reduced, then concentrated, cooled, crystallized, and dried.
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