English Synonyms
3-(4-Hydroxyphenyl)-L-Alanine;2-Amino-3-(4-Hydroxyphenyl)-Propanoic Acid;2-Amino-3-(P-Hydroxyphenyl)propionic Acid;4-Hydroxyphenylalanine;fema 3736;h-L-Tyr-Oh;h-Tyr-Oh;l-3-[4-Hydroxyphenyl]alanine
L-Tyrosine Properties
| Melting point | >300 °C (dec.) (lit.) |
| Specific rotation | -11.65 º (c=5,DIL HCL/H2O 50/50) |
| Boiling Point | 314.29°C (rough estimate) |
| Density | 1.34 |
| Refractive Index | -12 ° (C=5, 1mol/L HCl) |
| FEMA | 3736 | L-TYROSINE |
| Flash point | 176 °C |
| Storage conditions | Store below +30°C. |
| Solubility | 1MHCl：25 mg/mL |
| Form | powder |
| Acidity coefficient (pKa) | 2.2(at 25℃) |
| Color | White to light brown |
| Odor | Odorless |
| pH | 6.5 (0.1g/l, H2O) |
| Fragrance | odorless |
| Optical activity | [α]20/D 11.5±1.0°, c = 4% in 1 M HCl |
| Water solubility | 0.45 g/L (25 ºC) |
| JECFA Number | 1434 |
| Merck | 14,9839 |
| BRN | 392441 |
| Stability | Stable. Incompatible with strong oxidizing agents and strong reducing agents. |
| InChIKey | OUYCCCASQSFEME-QMMMGPOBSA-N |
| LogP | 0.38 |
Tyrosine
Tyrosine is an aromatic amino acid that exists in various proteins, and is particularly abundant in milk casein. The molecule contains phenol groups.
Tyrosine is a white crystalline powder with chemical properties. It crystallizes from water into needles or flakes. Relative density 1.456 (20°C), isoelectric point 5.66, has the ability to absorb ultraviolet rays, has maximum light absorption at a wavelength of 274nm, and can reduce phosphomolybdic acid-phosphotungstic acid reagent (Folin reagent).
Melting point: The left-handed body decomposes at 290-295°C (slow heating), decomposes at 314-318°C (rapid heating), the racemic body decomposes at 290-295 (slow heating), and decomposes at 340°C (rapid heating). Soluble in water, ethanol, acid and alkali, insoluble in ether. The aqueous solution of the right-handed body reacts with tyrosinase to appear red. The left-handed isomer can generate light by friction. When heated with a barium hydroxide aqueous solution at 170°C, it turns into a racemic isomer. The ortho position of the phenolic hydroxyl group in the tyrosine molecule is prone to chemical reaction. It is coupled with diazobenzenesulfonic acid to obtain an orange-red substance. It reacts with boiling dilute acetic acid and sodium nitrite to show purple or red, reacts with warm nitric acid to show yellow, and reacts with titanium dioxide in sulfuric acid to show dark orange-yellow. Natural tyrosine is a left-handed isomer and can be obtained by protein hydrolysis and refining. Tyrosine is a non-essential amino acid and a raw material for a variety of products in the body. Tyrosine can be converted into a variety of physiological substances in the body through different metabolic pathways, such as dopamine, adrenaline, thyroxine, melanin, and papaverine from poppy (opium). These substances are closely related to nerve conduction and metabolic regulation and control. Studying tyrosine metabolism helps to understand the pathological process of certain diseases. For example, alkaptonuria is related to tyrosine metabolism disorder. The patient lacks tyrosine oxidase, which causes the tyrosine metabolite 3,4-dihydroxyphenylalanine to be unable to further decompose and be excreted in the urine. When it encounters air, it is oxidized into a black substance. The diapers of children with this disease will gradually turn black when exposed to air, and this urine will also turn black if left for a long time. Albinism is also related to tyrosine metabolism. The patient lacks tyrosinase, which causes the tyrosine metabolite 3,4-dihydroxyphenylalanine to be unable to form melanin, resulting in white hair and skin.
Chemical properties
White needle-shaped crystals or crystalline powder, odorless, bitter taste, mp334℃ (decomposition), insoluble in water (0.04%, 25℃), insoluble in anhydrous ethanol, ether and acetone, soluble in dilute acid or dilute alkali. Isoelectric point 5.66.
Uses
Amino acid drugs. Raw materials for amino acid infusion and amino acid compound preparations, used as nutritional supplements. Used to treat poliomyelitis and tuberculous encephalitis/hyperthyroidism, etc.
Nutritional supplement. After heating with sugars to produce aminocarbonyl reaction, it can produce special flavor substances. It is used in medicine to treat hyperthyroidism.
It is used in biochemical research and in medicine as an amino acid nutrient to treat diseases such as poliomyelitis, encephalitis, and hyperthyroidism.
Biochemical reagents, APIs. Non-essential amino acids for the human body.
Biochemical research. Standard for determining nitrogen in amino acids. Preparation of tissue culture medium. Colorimetric quantitative analysis using the Milon reaction (protein color reaction). It is the main raw material for the synthesis of various peptide hormones, antibiotics and other drugs, and the amino acid precursor of dopamine and catecholamines.
Production method
1. Take casein as raw material, reflux in hydrochloric acid for several hours, filter, concentrate, neutralize with alkali, treat with activated carbon, and crystallize to obtain the product.
2. After separation of the precipitate produced by the neutralization of acid hydrolyzates of proteins such as casein and silk, dissolve in dilute ammonia water, neutralize with acetic acid to pH=5, and recrystallize to obtain it. The second crude crystallization pure liquid of cystine extracted from pig hair hydrolyzate is stored below 20℃ for two days to precipitate tyrosine, filter, and obtain crude tyrosine. L-tyrosine can also be obtained after refining. The yield for pig hair is 1%.
3. After separation of the precipitate produced by the neutralization of acid hydrolyzates of proteins such as casein or silk, dissolve in dilute ammonia water, neutralize with acetic acid to a Ph value of 5, and recrystallize to obtain it.
