Publications

• Licodione Synthase, a Cytochrome P450 Monooxygenase Catalyzing 2-Hydroxylation of 5-Deoxyflavanone, in Cultured Glycyrrhiza echinata L. Cells.

  Otani K., Takahashi T., Furuya T., Ayabe S.

  Cultured Glycyrrhiza echinata L. (Leguminosae) cells produce a retrochalcone echinatin (4,4[prime]-dihydroxy-2-methoxychalcone) and its biosynthetic intermediate licodione [1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)-1,3-propanedione, a dibenzoylmethane (keto form) or its enol tautomer ([beta]-hyd ... >> More

  Cultured Glycyrrhiza echinata L. (Leguminosae) cells produce a retrochalcone echinatin (4,4[prime]-dihydroxy-2-methoxychalcone) and its biosynthetic intermediate licodione [1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)-1,3-propanedione, a dibenzoylmethane (keto form) or its enol tautomer ([beta]-hydroxychalcone)], when treated with elicitor-active substances, e.g. yeast extract. A microsomal fraction (160,000g pellet) prepared from yeast extract-induced suspension cultures of G. echinata catalyzed the formation of licodione from (2S)-liquiritigenin (7,4[prime]-dihydroxyflavanone) in the presence of NADPH and air. This licodione synthase activity was shown to be dependent on cytochrome P450 by its microsomal localization, requirement of NAD(P)H and O2 for activity, and inhibition by typical cytochrome P450 inhibitors. Licodione synthase activity transiently increased in the cells after treatment with yeast extract. When (2S)-naringenin (5,7,4[prime]-trihydroxyflavanone) and NADPH were incubated with the same microsomal preparation, a polar compound, which further converted into apigenin (5,7,4[prime]-trihydroxyflavone) when treated with acid, was produced. The reaction mechanism of licodione synthase is likely to be 2-hydroxylation of the flavanone molecule and subsequent hemiacetal opening and is possibly the same as the previously suggested mechanism of flavone synthase II from soybean and, furthermore, closely related to isoflavone synthase from Pueraria lobata. << Less

  Plant Physiol 105:1427-1432(1994) [PubMed] [EuropePMC]

• Identification of a cytochrome P450 cDNA encoding (2S)-flavanone 2-hydroxylase of licorice (Glycyrrhiza echinata L. Fabaceae) which represents licodione synthase and flavone synthase II.

  Akashi T., Aoki T., Ayabe S.

  The microsome of insect cells expressing CYP Ge-5 (CYP93B1), a cytochrome P450 cDNA of licorice (Glycyrrhiza echinata L.), catalyzed the formation of [14C]licodione and [14C]2-hydroxynaringenin from (2S)-[14C]liquiritigenin and (2S)-[14C]naringenin, respectively. On acid treatment, the products we ... >> More

  The microsome of insect cells expressing CYP Ge-5 (CYP93B1), a cytochrome P450 cDNA of licorice (Glycyrrhiza echinata L.), catalyzed the formation of [14C]licodione and [14C]2-hydroxynaringenin from (2S)-[14C]liquiritigenin and (2S)-[14C]naringenin, respectively. On acid treatment, the products were converted to 14C-labeled 7,4'-dihydroxyflavone and apigenin. Eriodictyol was also converted to luteolin by the reaction with the microsome of yeast expressing CYP93B1 and subsequent acid treatment. CYP93B1 was thus shown to encode (2S)-flavanone 2-hydroxylase, which has previously been designated to licodione synthase and flavone synthase II depending on the substrates employed. << Less

  FEBS Lett. 431:287-290(1998) [PubMed] [EuropePMC]

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