title: Anthocyanin-producing dandelion callus as a chalcone synthase source in recombinant polyketide reductase assay.
abstract: Purple-coloured dandelion (Taraxacum officinale) callus cultures producing anthocyanin pigments were established on a cytokinin-rich medium under the light. When the cells were placed in the dark, only grey cells proliferated. Anthocyanin productivity of these cells was partially restored in the light. The major pigment was identified as cyanidin 3-(6"-malonylglucoside). The lower stem of the original plant contained the same pigment. Chalcone synthase (CHS) activity was detected in the extracts of these purple cells, whereas no activity was observed in grey cells propagated in the dark. When the CHS-active cell-free extract was combined with the extract of Escherichia coli over expressing polyketide reductase (PKR) cDNA of licorice (Glycyrrhiza echinata), isoliquiritigenin (a 6'-deoxychalcone), in addition to naringenin (a 5-hydroxyflavanone), was detected as the reaction product from 4-coumaroyl-CoA, malonyl-CoA and NADPH. This result confirms the catalytic function of the PKR gene product.
authors.affiliation: Department of Applied Biological Sciences, Nihon University, Kanagawa, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Akashi
authors.forename: N
authors.initials: N
authors.lastname: Saito
authors.forename: H
authors.initials: H
authors.lastname: Hirota
authors.forename: S
authors.initials: S
authors.lastname: Ayabe
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D000872:Anthocyanins / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000378:metabolism; D002478:Cells, Cultured; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D006035:Glycyrrhiza / Q000201:enzymology; D010088:Oxidoreductases / Q000378:metabolism*; D010936:Plant Extracts / Q000378:metabolism / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D010944:Plants / Q000201:enzymology / Q000378:metabolism*; D010946:Plants, Medicinal
chemical_list: D000872:Anthocyanins; D001426:Bacterial Proteins; D010936:Plant Extracts; D010940:Plant Proteins; D010088:Oxidoreductases; D000217:Acyltransferases; C020141:flavanone synthetase