4425 L-Tyrosine Tyrosine is an essential amino acid that readily passes the blood-brain barrier. Once in the brain, it is a precursor for the neurotransmitters dopamine, norepinephrine and epinephrine, better known as adrenalin. These neurotransmitters are an important part of the body's sympathetic nervous system, and their concentrations in the body and brain are directly dependent upon dietary tyrosine. Tyrosine is not found in large concentrations throughout the body, probably because it is rapidly metabolized. Folic acid, copper and vitamin C are cofactor nutrients of these reactions. Tyrosine is also the precursor for hormones, thyroid, catecholestrogens and the major human pigment, melanin. Tyrosine is an important amino acid in many proteins, peptides and even enkephalins, the body's natural pain reliever. Valine and other branched amino acids, and possibly tryptophan and phenylalanine may reduce tyrosine absorption. A number of genetic errors of tyrosine metabolism occur. Most common is the increased amount of tyrosine in the blood of premature infants, which is marked by decreased motor activity, lethargy and poor feeding. Infection and intellectual deficits may occur. Vitamin C supplements reverse the disease. Some adults also develop elevated tyrosine in their blood. This indicates a need for more vitamin C. More tyrosine is needed under stress, and tyrosine supplements prevent the stress-induced depletion of norepinephrine and can cure biochemical depression. However, tyrosine may not be good for psychosis. Many antipsychotic medications apparently function by inhibiting tyrosine metabolism. L-dopa, which is directly used in Parkinson's, is made from tyrosine. Tyrosine, the nutrient, can be used as an adjunct in the treatment of Parkinson's. Peripheral metabolism of tyrosine necessitates large doses of tyrosine, however, compared to L-dopa. 60-18-4 6057 C9H11NO3 White powder. 343 dec°C 479 mg/L (at 25°C) L-tyrosine is absorbed from the small intestine by a sodium-dependent active transport process. Tyrosine is produced in cells by hydroxylating the essential amino acid phenylalanine. This relationship is much like that between cysteine and methionine. Half of the phenylalanine required goes into the production of tyrosine; if the diet is rich in tyrosine itself, the requirements for phenylalanine are reduced by about 50%. The mechanism of L-tyrosine's antidepressant activity can be accounted for by the precursor role of L-tyrosine in the synthesis of the neurotransmitters norepinephrine and dopamine. Elevated brain norepinephrine and dopamine levels are thought to be associated with antidepressant effects. In the liver, L-tyrosine is involved in a number of biochemical reactions, including protein synthesis and oxidative catabolic reactions. L-tyrosine that is not metabolized in the liver is distributed via the systemic circulation to the various tissues of the body. LD₅₀ (oral, rat) > 5110 mg/kg No indication of carcinogenicity to humans (not listed by IARC). Tyrosine is claimed to act as an effective antidepressant, however results are mixed. Tyrosine has also been claimed to reduce stress and combat narcolepsy and chronic fatigue, however these claims have been refuted by some studies. 2014-08-29T06:35:59Z 2026-05-14T16:24:11Z L-Tyrosine C01536 17895 TYR DB00135 TYR true N[C@@H](CC1=CC=C(O)C=C1)C(O)=O C9H11NO3 InChI=1S/C9H11NO3/c10-8(9(12)13)5-6-1-3-7(11)4-2-6/h1-4,8,11H,5,10H2,(H,12,13)/t8-/m0/s1 OUYCCCASQSFEME-QMMMGPOBSA-N 181.1885 181.073893223 Endogenous Solid -2.26 HMDB00158 CHEMBL925 5833 <p>Hai-quan Mao, Kam W. Leong, &#8220;Biodegradable poly (phosphoester-co-desaminotyrosyl L-tyrosine ester) compounds, compositions, articles and methods for making and using the same.&#8221; U.S. Patent US5912225, issued May, 1960.</p> CHEM003331 DTXSID1023730 NS00001880 (2S)-2-amino-3-(4-hydroxyphenyl)propanoic acid 83.55 47.09720000000001 18.011281585436166 3 4 3 1.9998472511533611 9.185299922384795 0 1 -2.39 -1.37 7.67e+00 g/l