Shikimate Pathway
The shikimate pathway is a metabolic pathway that synthesizes aromatic amino acids, such as phenylalanine, tyrosine, and tryptophan, and a variety of other aromatic compounds, such as quinones, flavonoids, and lignin.Stages
Stage 1: The synthesis of shikimate from phosphoenolpyruvate (PEP) and erythrose 4-phosphate.- This step is catalyzed by the enzyme 3-dehydroquinate synthase (DHS).
- DHS condenses PEP and erythrose 4-phosphate to form 3-dehydroquinate. 3-dehydroquinate is then reduced to shikimate by the enzyme shikimate dehydrogenase (SDH).
Stage 2: The conversion of shikimate to chorismate.
- The key enzymes in this stage are shikimate kinase (SK), 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), chorismate synthase (CS), and chorismate mutase (CM).
Stage 3: The conversion of chorismate to aromatic amino acids and other aromatic compounds.
- Chorismate can be converted to a variety of aromatic amino acids and other aromatic compounds, including phenylalanine, tyrosine, tryptophan, quinones, flavonoids, and lignin.
Significance
- It is the only known pathway for the synthesis of aromatic amino acids, which are essential for protein synthesis and other cellular processes.
- Aromatic amino acids are also precursors to a variety of other important biomolecules, such as hormones, neurotransmitters, and signaling molecules.
- The shikimic acid pathway is also involved in the synthesis of secondary metabolites, such as antibiotics, pigments, and flavor compounds.
- The shikimic acid pathway is essential for plant growth and development.
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