EC 2.3.1.211     
Accepted name: bisdemethoxycurcumin synthase
Reaction: 2 4-coumaroyl-CoA + malonyl-CoA + H2O = 3 CoA + bisdemethoxycurcumin + 2 CO2
Glossary: bisdemethoxycurcumin = (1E,6E)-5-hydroxy-1,7-bis(4-hydroxyphenyl)hepta-1,4,6-trien-3-one
Other name(s): CUS; curcuminoid synthase (ambiguous)
Systematic name: 4-coumaroyl-CoA:malonyl-CoA 4-coumaryltransferase (bisdemethoxycurcumin-forming)
Comments: A polyketide synthase characterized from the plant Oryza sativa (rice) that catalyses the formation of the C6-C7-C6 diarylheptanoid scaffold of bisdemethoxycurcumin. Unlike the process in the plant Curcuma longa (turmeric), where the conversion is carried out via a diketide intermediate by two different enzymes (EC 2.3.1.218, phenylpropanoylacetyl-CoA synthase and EC 2.3.1.217, curcumin synthase), the diketide intermediate formed by this enzyme remains within the enzyme’s cavity and is not released to the environment.
References:
1.  Morita, H., Wanibuchi, K., Nii, H., Kato, R., Sugio, S. and Abe, I. Structural basis for the one-pot formation of the diarylheptanoid scaffold by curcuminoid synthase from Oryza sativa. Proc. Natl. Acad. Sci. USA 107 (2010) 19778–19783. [PMID: 21041675]
[EC 2.3.1.211 created 2013]
 
 
EC 2.3.1.218     
Accepted name: phenylpropanoylacetyl-CoA synthase
Reaction: (1) feruloyl-CoA + malonyl-CoA = feruloylacetyl-CoA + CO2 + CoA
(2) 4-coumaroyl-CoA + malonyl-CoA = (4-coumaroyl)acetyl-CoA + CO2 + CoA
Glossary: feruloylacetyl-CoA = feruloyl-diketide-CoA
(4-coumaroyl)acetyl-CoA = 4-coumaroyl-diketide-CoA
phenylpropanoylacetyl-CoA = phenylpropanoyl-diketide-CoA
Other name(s): phenylpropanoyl-diketide-CoA synthase; DCS
Systematic name: phenylpropanoyl-CoA:malonyl-CoA phenylpropanoyl-transferase (decarboxylating)
Comments: The enzyme has been characterized from the plant Curcuma longa (turmeric). It prefers feruloyl-CoA, and has no activity with cinnamoyl-CoA.
References:
1.  Katsuyama, Y., Kita, T., Funa, N. and Horinouchi, S. Curcuminoid biosynthesis by two type III polyketide synthases in the herb Curcuma longa. J. Biol. Chem. 284 (2009) 11160–11170. [PMID: 19258320]
[EC 2.3.1.218 created 2013]