 Shikimate dehydrogenase is an enzyme that catalyzes one step of the shikimate pathway.This pathway is found in bacteria, plants, fungi, algae, and parasites and is responsible for the biosynthesis of aromatic amino acids (phenylalanine, tyrosine, and tryptophan) from the metabolism of carbohydrates.In contrast, animals and humans lack this pathway hence products of this biosynthetic route are essential amino acids that must be obtained through an animal's diet.