@Article{IPB-2182,
author = {Samappito, S. and Page, J. and Schmidt, J. and De-Eknamkul, W. and Kutchan, T. M.},
title = {{Molecular characterization of root-specific chalcone synthases from Cassia alata}},
year = {2002},
pages = {64-71},
journal = {Planta},
doi = {10.1007/s00425-002-0872-8},
volume = {216},
abstract = {Three cDNAs encoding very similar but unique isoforms of chalcone synthase (EC 2.3.1.74) were isolated from a cDNA library prepared from RNA from root tissue of the Thai medicinal plant Cassia alata L. (ringworm bush, Leguminosae). Gene transcript for these three type-III polyketide synthases was found to accumulate predominantly in roots. The heterologously expressed enzymes accepted acetyl-, n-butyryl-, isovaleryl-, n-hexanoyl-, benzoyl-, cinnamoyl-, and p-coumaroyl-CoA as starter molecules and together with the co-substrate malonyl-CoA, formed multiple products. With the exception of the assay in which acetyl-CoA was used as the starter molecule, all substrates yielded a phloroglucinol derivative resulting from three sequential condensations of acetate units derived from three malonyl-CoA decarboxylations. Every substrate tested also produced two pyrone derivatives, one resulting from two acetate unit condensations (a bis-noryangonin-type pyrone derailment product) and one resulting from three acetate unit condensations (a 4-coumaroyltriacetic acid lactone-type pyrone derailment). C. alata accumulates the flavonoids quercetin, naringenin and kaempferol in roots, suggesting that the in planta function of these enzymes is the biosynthesis of root flavonoids.}    
}