Information AboutTyrosine |
| CATEGORIES ABOUT TYROSINE | |
| proteinogenic amino acids | |
| glucogenic amino acids | |
| ketogenic amino acids | |
| aromatic amino acids | |
| phenols | |
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Tyrosine (from the Greek ''tyros'', meaning ''cheese'', as it was first discovered in cheese), '''4-hydroxyphenylalanine''', or '''2-amino-3(4-hydroxyphenyl)-propanoic acid''', is one of the 20 Amino Acid s that are used by Cells to Synthesize Protein s. It has a Phenol side chain. Tyrosine is converted to DOPA by Tyrosine hydroxylase, an enzyme. It plays a key role in Signal Transduction , since it can be ''tagged'' with a phosphate group ( Phosphorylated ) by Protein Kinase s to alter the functionality and activity of certain Enzyme s. (In its phosphorylated state, it is sometimes referred to as phosphotyrosine.) Tyrosine is also precursor to the Thyroid Hormone s '' Thyroxine '' and '' Triiodothyronine '', the pigment '' Melanin '', and the biologically-active Catecholamine s '' Dopamine '', '' Norepinephrine '' and '' Epinephrine ''. In Papaver Somniferum , the opium poppy, it is used to produce Morphine . BIOSYNTHESIS Tyrosine cannot be completely synthesized by animals, although it can be made by hydroxylation of Phenylalanine if the latter is in abundant supply. It is produced by plants and most microorganisms from Prephenate , an intermediate on the Shikimate Pathway . Prephenate is Oxidatively Decarboxylated with retention of the Hydroxyl group to give ''p''-hydroxyphenylpyruvate. This is Transaminated using Glutamate as the nitrogen source to give tyrosine and α-ketoglutarate . TYROSINE HYDROXYLASE Tyrosine hydroxylase (TH) is the rate-limiting Enzyme involved in the synthesis of the Catecholamines (Dopamine, Norepinephrine, Epinephrine). SEE ALSO EXTERNAL LINKS |
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