Chorismate is an intermediate in tyrosine, phenylalanine and tryptophan synthesis and a precursor for folic acid, ubiquinone, enterochelin and menaquinone. Three enzymes catalyze the first step in chorismate biosynthesis. Synthesis may be reduced by feedback inhibition of tyrosine, phenylalanine and tryptophan to the enzymes. The biosynthesis of chorismate starts with D-Erythrose-4-phosphate getting transformed into 3-deoxy-D-arabino-heptulosonate-7-phosphate through a phospho-2-dehydro-3-deoxyheptonate aldolase. This is followed by a 3-dehydroquinate synthase converting the 3-deoxy-D-arabino-heptulosonate-7-phosphate into a 3-dehydroquinate which in turn is conveted to 3-dehydroshikimate through a 3-dehydroquinate dehydratase. At this point 3-dehydroshikimate can be turned into Shikimic acid through 2 different reactions involving Quinate/shikimate dehydrogenase and shikimate dehydrogenase 2. Shikimic acid is phosphorylated by Shikimate kinase 2 into shikimate 3-phosphate. Shikimate 3- phophate and a phosphoenolpyruvic acid are then joined through a 3-phosphoshikimate 1-carboxyvinyltransferase to produce a 5-enoylpyruvyl-shikimate 3-phosphate while releasing a phosphate. This in turn produces our final product Chorismate through a chorismate synthase.

Chorismate Biosynthesis References