Shikimate pathway Shikimic acid

1 shikimate pathway

1.1 biosynthesis of aromatic amino acids
1.2 starting point in biosynthesis of phenolics
1.3 other compounds

1.3.1 mycosporine-like amino acids

shikimate pathway

biosynthesis of aromatic amino acids

the shikimate pathway 7 step metabolic route used bacteria, fungi, algae, parasites, , plants biosynthesis of aromatic amino acids (phenylalanine, tyrosine, , tryptophan). pathway not found in animals; therefore, phenylalanine , tryptophan represent essential amino acids must obtained animal s diet (animals can synthesise tyrosine phenylalanine, , therefore not essential amino acid except individuals unable hydroxylate phenylalanine tyrosine).

the 7 enzymes involved in shikimate pathway dahp synthase, 3-dehydroquinate synthase, 3-dehydroquinate dehydratase, shikimate dehydrogenase, shikimate kinase, epsp synthase, , chorismate synthase. pathway starts 2 substrates, phosphoenol pyruvate , erythrose-4-phosphate , ends chorismate, substrate 3 aromatic amino acids. fifth enzyme involved shikimate kinase, enzyme catalyzes atp-dependent phosphorylation of shikimate form shikimate 3-phosphate (shown in figure below). shikimate 3-phosphate coupled phosphoenol pyruvate give 5-enolpyruvylshikimate-3-phosphate via enzyme 5-enolpyruvylshikimate-3-phosphate (epsp) synthase.

then 5-enolpyruvylshikimate-3-phosphate transformed chorismate chorismate synthase.

prephenic acid synthesized claisen rearrangement of chorismate chorismate mutase.

prephenate oxidatively decarboxylated retention of hydroxyl group give p-hydroxyphenylpyruvate, transaminated using glutamate nitrogen source give tyrosine , α-ketoglutarate.

starting point in biosynthesis of phenolics

phenylalanine , tyrosine precursors used in phenylpropanoids biosynthesis. phenylpropanoids used produce flavonoids, coumarins, tannins , lignin. first enzyme involved phenylalanine ammonia-lyase (pal) converts l-phenylalanine trans-cinnamic acid , ammonia.

gallic acid biosynthesis

gallic acid formed 3-dehydroshikimate action of enzyme shikimate dehydrogenase produce 3,5-didehydroshikimate. latter compound spontaneously rearranges gallic acid.

other compounds

shikimic acid precursor for:

indole, indole derivatives , aromatic amino acid tryptophan , tryptophan derivatives such psychedelic compound dimethyltryptamine
many alkaloids , other aromatic metabolites

mycosporine-like amino acids

mycosporine-like amino acids small secondary metabolites produced organisms live in environments high volumes of sunlight, marine environments.