|
In enzymology, a chorismate synthase () is an enzyme that catalyzes the chemical reaction :5-O-(1-carboxyvinyl)-3-phosphoshikimate chorismate + phosphate Hence, this enzyme has one substrate, 5-O-(1-carboxyvinyl)-3-phosphoshikimate, and two products, chorismate and phosphate. This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. The systematic name of this enzyme class is 5-O-(1-carboxyvinyl)-3-phosphoshikimate phosphate-lyase (chorismate-forming). This enzyme is also called 5-O-(1-carboxyvinyl)-3-phosphoshikimate phosphate-lyase. This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis. Chorismate synthase catalyzes the last of the seven steps in the shikimate pathway which is used in prokaryotes, fungi and plants for the biosynthesis of aromatic amino acids. It catalyzes the 1,4-trans elimination of the phosphate group from 5-enolpyruvylshikimate-3-phosphate (EPSP) to form chorismate which can then be used in phenylalanine, tyrosine or tryptophan biosynthesis. Chorismate synthase requires the presence of a reduced flavin mononucleotide (FMNH2 or FADH2) for its activity. Chorismate synthase from various sources shows a high degree of sequence conservation. It is a protein of about 360 to 400 amino-acid residues. ==Biological and Practical Function== The shikimate pathway synthesises aromatic amino acids as well as other aromatic compounds that have various involvement with processes such as "UV protection, electron transport, signaling, communication, plant defense, and the wound response". Moreover, the enzymes catalysing the Shikimate pathway may be potentially useful in the development of new herbicides and antibiotics. This is due to the fact that the shikimate pathway is not present in humans. It is, therefore, an ideal target for herbicides because chemicals used to inhibit the shikimate pathway should not have an effect on humans. Also, the products created by the shikimate pathway are essential to plant life, so, if the function of the pathway is inhibited, this has a fatal effect on the plant. The enzymes in the shikimate pathway, and chorismate synthase specifically,are also considered to be potential targets for new antimicrobial chemotherapy treatments for Mycobacterium tuberculosis. This is important since drugs resistant strains of M. tuberculosis continue to emerge. Studies have shown that the "shikimate pathway is essential for M. tuberculosis viability" making it an attractive target for new antimycobacterial agents. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chorismate synthase」の詳細全文を読む スポンサード リンク
|