|
Sponsored Links
Tyrosine (abbreviated as Tyr or Y)[1] or 4-hydroxyphenylalanine, is one of the 20 amino acids that are used by cells to synthesize proteins. This is a non-essential amino acid and it is found in casein. In fact, the word "tyrosine" is from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese.[2][3] Aside from being a proteogenic amino acid, tyrosine has a special role by virtue of the phenol functionality. It occurs in proteins that are part of signal transduction processes. It functions as a receiver of phosphate groups that are transferred by way of protein kinases (so-called receptor tyrosine kinases). Phosphorylation of the hydroxyl group changes the activity of the target protein. A tyrosine residue also plays an important role in photosynthesis. In chloroplasts (photosystem II), it acts as an electron donor in the reduction of oxidized chlorophyll. In this process, it undergoes deprotonation of its phenolic OH-group. This radical is subsequently reduced in the photosystem II by the four core manganese cluster. In plants and most microorganisms, tyr is produced via prephenate, an intermediate on the shikimate pathway. Prephenate is oxidatively decarboxylated with retention of the hydroxyl group to give p-hydroxyphenylpyruvate, which is transaminated using glutamate as the nitrogen source to give tyrosine and a-ketoglutarate.
|
Tyrosine Subcategories
Tyrosine Articles
|
| 
