Chalcone isomerase

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chalcone isomerase
EC number
CAS number 9073-57-8
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
Chalcone isomerase
PDB 1jep EBI.jpg
chalcone isomerase complexed with 4'-hydroxyflavanone
Symbol Chalcone
Pfam PF02431
InterPro IPR003466
SCOP 1eyp

In enzymology, a chalcone isomerase (EC is an enzyme that catalyzes the chemical reaction

a chalcone a flavanone

Hence, this enzyme has one substrate, a chalcone, and one product, a flavanone.

This enzyme belongs to the family of isomerases, specifically the class of intramolecular lyases. The systematic name of this enzyme class is flavanone lyase (decyclizing). This enzyme is also called chalcone-flavanone isomerase. This enzyme participates in flavonoid biosynthesis.

The Petunia hybrida (Petunia) genome contains two genes coding for very similar enzymes, ChiA and ChiB, but only the first seems to encode a functional chalcone isomerase.

Structural studies[edit]

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1EYP, 1EYQ, 1FM7, 1FM8, 1JEP, 1JX0, and 1JX1.

Chalcone isomerase has a core 2-layer alpha/beta structure consisting of beta(3)-alpha(2)-beta-alpha(2)-beta(3).[1]


  1. ^ Jez JM, Bowman ME, Dixon RA, Noel JP (September 2000). "Structure and mechanism of the evolutionarily unique plant enzyme chalcone isomerase". Nat. Struct. Biol. 7 (9): 786–91. doi:10.1038/79025. PMID 10966651. 

Further reading[edit]

This article incorporates text from the public domain Pfam and InterPro: IPR003466