Polyketide

Polyketides are secondary metabolites from bacteria, fungi, plants, and animals. As typical for secondary metabolites, polyketides are dispensable for normal growth of the organism producing it, but may inhibit growth of other organisms or have roles as compounds involved in biological signalling. Polyketides are synthesized in vivo by the polymerization of acetyl and propionyl subunits in a similar process to fatty acid synthesis. Robinson JA (1991). "Polyketide synthase complexes: their structure and function in antibiotic biosynthesis". Philos Trans R Soc Lond B Biol Sci. 332: 107-114. PMID 1678529.  They are the building blocks for a broad range of natural products or are further derivatized.

Polyketides are structurally a very diverse family of natural products with an extremely broad range of biological activities and pharmacological properties. Polyketide antibiotics, antifungals, cytostatics, anticholesterolemics, antiparasitics, coccidiostatics, animal growth promoters and natural insecticides are in commercial use.^{[citation needed]}

Examples

• Macrolides
  • Picromycin, the first isolated macrolide (1950)
  • The antibiotics erythromycin A, clarithromycin, and azithromycin
  • The immunosuppressant tacrolimus (FK506)
• Polyene antibiotics
  • Amphotericin
• Tetracyclines
  • The tetracycline family of antibiotics
• Others
  • Discodermolide
  • Aflatoxin

Biosynthesis

Polyketides are synthesized by one or more specialized and highly complex polyketide synthase (PKS) enzymes.

References

See also

• Esterase
• Nonribosomal peptide

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