PROSITE documentation PDOC00403 [for PROSITE entry PS00441]

Chalcone and stilbene synthases active site


Chalcone synthases (CHS) (EC and stilbene synthases (STS) (formerly known as resveratrol synthases) are related plant enzymes [1]. CHS is an important enzyme in flavanoid biosynthesis and STS a key enzyme in stilbene-type phyloalexin biosynthesis. Both enzymes catalyze the addition of three molecules of malonyl-CoA to a starter CoA ester (a typical example is 4-coumaroyl-CoA), producing either a chalcone (with CHS) or stilbene (with STS).

These enzymes are proteins of about 390 amino-acid residues. A conserved cysteine residue, located in the central section of these proteins, has been shown [2] to be essential for the catalytic activity of both enzymes and probably represents the binding site for the 4-coumaryl-CoA group. The region around this active site residue is well conserved and can be used as a signature pattern.

In addition to the plant enzymes, this family also includes Bacillus subtilis bcsA.

Expert(s) to contact by email:

Schroeder J.

Last update:

December 2004 / Pattern and text revised.

Technical section

PROSITE method (with tools and information) covered by this documentation:

CHALCONE_SYNTH, PS00441; Chalcone and stilbene synthases active site  (PATTERN)


1AuthorsSchroeder J., Schroeder G.
SourceZ. Naturforsch. 45C:1-8(1990).

2AuthorsLanz T., Tropf S., Marner F.-J., Schroeder J., Schroeder G.
TitleThe role of cysteines in polyketide synthases. Site-directed mutagenesis of resveratrol and chalcone synthases, two key enzymes in different plant-specific pathways.
SourceJ. Biol. Chem. 266:9971-9976(1991).
PubMed ID2033084

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to
Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)