Shikimic acid pathway
Shikimic acid, more commonly known as its anionic form shikimate, is an important biochemical metabolite in plants and microorganisms.
Its name comes from the Japanese flower shikimi from which it was first isolated. * Shikimic acid is a precursor for : * The aromatic amino acids phenylalanine and tyrosine * Indole, indole derivatives and aromatic amino acid tryptophan * Many alkaloids and other aromatic metabolites * Phenylpropanoids, flavonoids, tannins, and lignin.

Biosynthesis of 3-dehydroquinate from phosphoenolpyruate and erythrose-4-phosphate
DHQ is dehydrated to 3-dehydroshikimic acid by the enzyme dehydroquinase, which is reduced to shikimic acid by the enzyme shikimate dehydrogenase, which uses nicotinamide adenine dinucleotide phosphate (NADPH) as a cofactor.

Biosynthesis of shikimic acid from 3-dehydroquinate
The shikimate pathway is a seven step metabolic route used by bacteria, fungi, algae, parasites and plants for the biosynthesis of aromatic amino acids (phenylalanine, tyrosine, and tryptophan). This pathway is not found in animals and in humans, hence the products of this pathway represent essential amino acids that must be obtained from the animal's diet.
The first enzyme involved is the shikimate kinase, an enzyme that catalyzes the ATP-dependent phosphorylation of shikimate to form shikimate 3-phosphate.[7] Shikimate 3-phosphate is then coupled with phosphoenol pyruvate to give 5-enolpyruvylshikimate-3-phosphate via the enzyme 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase.
Then 5-enolpyruvylshikimate-3-phosphate is transformed into chorismate by a chorismate synthase.
Prephenic acid is then synthesized by a rearrangement of chorismate
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 α-ketoglutarate.