<p>The bifunctional T-protein (TyrA), which plays a central role in tyrosine biosynthesis, contains two catalytic domains (chorismate mutase and prephenate dehydrogenase). It is part of the shikimate pathway, which is present only in bacteria, fungi and plants. It is feedback inhibited by tyrosine. Chorismate mutase (CM; <db_xref db="EC" dbkey="5.4.99.5"/>) catalyses the rearrangement of chorismate to prephenate, the reaction at the branch point of the biosynthetic pathway leading to the three aromatic amino acids, phenylalanine, tryptophan and tyrosine (chorismic acid is the last common intermediate, and CM leads to the L-phenylalanine/L-tyrosine branch). The chorismate mutase domain of this protein belongs to the AroQ class (Prokaryotic type), and has an all-helical structure. There are stand-alone versions of this domain (e.g., <db_xref db="INTERPRO" dbkey="IPR008239"/>), as well as fusions to other catalytic domains (prephenate dehydratase, <db_xref db="INTERPRO" dbkey="IPR008242"/>; 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase, <db_xref db="PIRSF" dbkey="PIRSF005994"/>), or to regulatory domains. Prephenate dehydrogenase (PDH; <db_xref db="EC" dbkey="1.3.1.12"/>) catalyses the oxidative decarboxylation of prephenate to 4-hydroxyphenylpyruvate.</p> <p>For additional information please see [<cite idref="PUB00011079"/>, <cite idref="PUB00011057"/>, <cite idref="PUB00011080"/>, <cite idref="PUB00011058"/>, <cite idref="PUB00011045"/>, <cite idref="PUB00011066"/>, <cite idref="PUB00011067"/>].</p>