Flavanone 8-dimethylallyltransferase in Sophora flavescens cell suspension cultures

Abstract

Dimethylallyl diphosphate: naringenin 8-dimethylallyltransferase (EC 2.5.1) was characterized. The enzyme was enantiospecific for (−)-(2 S)-naringenin and utilized 3,3-dimethylallyl diphosphate as sole prenyl donor. It required Mg 2+ (optimum concentration, 10 mM), and has an optimum pH of 9–10. The apparent K m values for 3,3-dimethylallyl diphosphate and naringenin were 120 and 36 μM, 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.