Chalcone/stilbene synthase, N-terminal Synonym(s): Chalcone synthase, Flavonone synthase, 6'-deoxychalcone synthase <p>Naringenin-chalcone synthases (<db_xref db="EC" dbkey="2.3.1.74"/>) and stilbene synthases (STS) (formerly known as resveratrol synthases) are related plant enzymes. CHS is an important enzyme in flavanoid biosynthesis and STS is a key enzyme in stilbene-type phyloalexin biosynthesis. Both enzymes catalyse 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) [<cite idref="PUB00005665"/>].</p><p>These enzymes have a conserved cysteine residue, located in the central sectionof the protein sequence, which is essential for the catalytic activity of bothenzymes and probably represents the binding site for the 4-coumaryl-CoA group[<cite idref="PUB00002705"/>].</p>