Are the characteristics of betanidin glucosyltransferases from cell-suspension cultures Dorotheanthus bellidiformis indicative of their phylogenetic relationship with flavonoid glucosyltransferases?

• Published in: Planta Vol. 203; no. 3; pp. 349 - 361
• Main Authors: Vogt, T, Zimmermann, E, Grimm, R, Meyer, M, Strack, D
• Format: Journal Article
• Language: English
• Published: Germany Springer-Verlag 1997
• Subjects: Amino Acid Sequence; amino acid sequences; anthocyanidins; anthocyanins; Betacyanins; biochemical pathways; Biotechnology; caffeic acid; Cell culture techniques; cell suspension culture; Cells, Cultured; Chromatography; Chromatography, Affinity; Chromatography, Gel; Chromatography, Ion Exchange; dihydroxyphenylalanine; Dorotheanthus bellidiformis; Elution; enzyme activity; enzyme inhibitors; Enzymes; flavones; Flavonoids; Flavonoids - metabolism; flavonols; glucose; Glucosides; Glucosyltransferases - chemistry; Glucosyltransferases - isolation & purification; Glucosyltransferases - metabolism; hexosyltransferases; Hydroxyls; isoelectric point; Kinetics; Molecular Sequence Data; Molecular Weight; Phylogeny; physicochemical properties; Plant Cells; Plants; Plants - enzymology; quercetin; Sequence Alignment; Sequence Homology, Amino Acid; Substrate Specificity
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s004250050201

Uridine 5'-diphosphoglucose:betanidin 5-O-and 6-O-glucosyltransferases (5-GT and 6-GT: EC 2.4.1) catalyze the regiospecific formation of betanin (beta- nidin 5-O-beta-glucoside) and gomphrenin I (betanidin 6-O-beta-glucoside), respectively. Both enzymes were purified to near homogeneity from cell-suspension cultures of Dorotheanthus bellidiformis, the 5-GT by classical chromatographic techniques and the 6-GT by affinity dye-ligand chromatography using UDP-glucose as eluent. Data obtained with highly purified enzymes indicate that 5-GT and 6-GT catalyze the indiscriminate transfer of glucose from UDP-glucose to hydroxyl groups of betanidin, flavonols, anthocyanidins and flavones, but discriminate between individual hydroxyl groups of the respective acceptor compounds. The 5-GT catalyzes the transfer of glucose to the C-4' hydroxyl group of quercetin as its best substrate, and the 6-GT to the C-3 hydroxyl group of cyanidin as its best substrate. Both enzymes also catalyze the formation of the respective 7-O-glucosides, but to a minor extent. Although the enzymes were not isolated to homogeneity, chromatographic, electrophoretic and kinetic properties proved that the respective enzyme activities were based on the presence of single enzymes, i.e. 5-GT and 6-GT. The N terminus of the 6-GT revealed high sequence identity to a proposed UDP-glucose:flavonol 3-O-glucosyltransferase (UF3GT) of Manihot esculenta. In addition to the 5-GT and 6-GT, we isolated a UF3GT from D. bellidiformis cell cultures that preferentially accepted myricetin and quercetin, but was inactive with betanidin. The same result was obtained with a UF3GT from Antirrhinum majus and a flavonol 4'-O-glucosyl-transferase from Allium cepa. Based on these results, the main question to be addressed reads: Are the characteristics of the 5-GT and 6-GT indicative of their phylogenetic relationship with flavonoid glucosyltransferases?