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

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 (2 S)-[ 14C]liquiritigenin and (2 S)-[ 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 (2 S)-flavanone 2-hydroxylase, which has previously been designated to licodione synthase and flavone synthase II depending on the substrates employed.