Publications

• Cloning and Characterization of Naringenin 8-Prenyltransferase, a Flavonoid-Specific Prenyltransferase of Sophora flavescens.

  Sasaki K., Mito K., Ohara K., Yamamoto H., Yazaki K.

  Prenylated flavonoids are natural compounds that often represent the active components in various medicinal plants and exhibit beneficial effects on human health. Prenylated flavonoids are hybrid products composed of a flavonoid core mainly attached to either 5-carbon (dimethylallyl) or 10-carbon ... >> More

  Prenylated flavonoids are natural compounds that often represent the active components in various medicinal plants and exhibit beneficial effects on human health. Prenylated flavonoids are hybrid products composed of a flavonoid core mainly attached to either 5-carbon (dimethylallyl) or 10-carbon (geranyl) prenyl groups derived from isoprenoid (terpenoid) metabolism, and the prenyl groups are crucial for their biological activity. Prenylation reactions in vivo are crucial coupling processes of two major metabolic pathways, the shikimate-acetate and isoprenoid pathways, in which these reactions are also known as a rate-limiting step. However, none of the genes responsible for the prenylation of flavonoids has been identified despite more than 30 years of research in this field. We have isolated a prenyltransferase gene from Sophora flavescens, SfN8DT-1, responsible for the prenylation of the flavonoid naringenin at the 8-position, which is specific for flavanones and dimethylallyl diphosphate as substrates. Phylogenetic analysis shows that SfN8DT-1 has the same evolutionary origin as prenyltransferases for vitamin E and plastoquinone. The gene expression of SfN8DT-1 is strictly limited to the root bark where prenylated flavonoids are solely accumulated in planta. The ectopic expression of SfN8DT-1 in Arabidopsis thaliana resulted in the formation of prenylated apigenin, quercetin, and kaempferol, as well as 8-prenylnaringenin. SfN8DT-1 represents the first flavonoid-specific prenyltransferase identified in plants and paves the way for the identification and characterization of further genes responsible for the production of this large and important class of secondary metabolites. << Less

  Plant Physiol. 146:1075-1084(2008) [PubMed] [EuropePMC]

• Flavanone 8-dimethylallyltransferase in Sophora flavescens cell suspension cultures.

  Yamamoto H., Senda M., Inoue K.

  Dimethylallyl diphosphate: naringenin 8-dimethylallyltransferase (EC 2.5.1) was characterized. The enzyme was enantiospecific for (-)-(2S)-naringenin and utilized 3,3-dimethylallyl diphosphate as sole prenyl donor. It required Mg2+ (optimum concentration, 10 mM), and has an optimum pH of 9-10. The ... >> More

  Dimethylallyl diphosphate: naringenin 8-dimethylallyltransferase (EC 2.5.1) was characterized. The enzyme was enantiospecific for (-)-(2S)-naringenin and utilized 3,3-dimethylallyl diphosphate as sole prenyl donor. It required Mg2+ (optimum concentration, 10 mM), and has an optimum pH of 9-10. The apparent Km values for 3,3-dimethylallyl diphosphate and naringenin were 120 and 36 microM, respectively. The microsomal fraction prenylated several other flavanones at the C-8 position less effectively as compared with naringenin. Interestingly, when 2'-hydroxynaringenin was used as a prenyl acceptor, the 8-lavandulyl (sophoraflavanone G) and the 6-dimethylallyl derivatives were formed, together with the 8-dimethylallyl derivative, leachianone G. These results suggest that the 2'-hydroxy group of naringenin plays an important role for the formation of a lavandulyl group. << Less

  Phytochemistry 54:649-655(2000) [PubMed] [EuropePMC]

• Characterization of leachianone G 2"-dimethylallyltransferase, a novel prenyl side-chain elongation enzyme for the formation of the lavandulyl group of sophoraflavanone G in Sophora flavescens Ait. cell suspension cultures.

  Zhao P., Inoue K., Kouno I., Yamamoto H.

  Leachianone G (LG) 2"-dimethylallyltransferase, a novel prenyl side-chain elongation enzyme, was identified in Sophora flavescens Ait. cultured cells. The enzyme transfers a dimethylallyl group to the 2" position of another dimethylallyl group attached at position 8 of LG to form sophoraflavanone ... >> More

  Leachianone G (LG) 2"-dimethylallyltransferase, a novel prenyl side-chain elongation enzyme, was identified in Sophora flavescens Ait. cultured cells. The enzyme transfers a dimethylallyl group to the 2" position of another dimethylallyl group attached at position 8 of LG to form sophoraflavanone G, a branched monoterpenoid-conjugated flavanone characteristic to this plant. This membrane-bound dimethylallyltransferase required Mg2+ (optimum concentration was 10 mm) for the reaction and had an optimum pH of 8.8. It utilized dimethylallyl diphosphate as the sole prenyl donor, and the 2'-hydroxy function in LG was indispensable to the activity. The apparent Km values for dimethylallyl diphosphate and LG were 59 and 2.3 microm, respectively. Subcellular localization of three enzymes that participated in the formation of the lavandulyl group was also investigated by sucrose density gradient centrifugation. Two prenyltransferases, naringenin 8-dimethylallyltransferase and LG 2"-dimethylallyltransferase, were localized in the plastids, whereas 8-dimethylallylnaringenin 2'-hydroxylase, which catalyzes the crucial step in the lavandulyl-group formation, was associated with the endoplasmic reticulum. These results suggest the close cooperation between the plastids and the endoplasmic reticulum in the formation of lavandulyl groups. << Less

  Plant Physiol 133:1306-1313(2003) [PubMed] [EuropePMC]

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