Anthocyanin Biosynthesis in Flowers of Matthiola Incana Flavanone 3- and Flavonoid 3'-Hydroxylases

Anthocyanins, Flavonoids, Biosynthesis, Flavanon 3-Hydroxylase, Flavonoid 3'-Hydroxylase, Matthiola incana. Enzyme preparations from flowers of defined genotypes of Matthiola incana contain two different hydroxylases for hydroxylation of naringenin in the 3- and 3'-position, respectively. The 3-hydroxylase is a soluble enzyme and requires as cofactors 2-oxoglutarate, Fe²⁺ and ascorbate. Besides naringenin eriodictyol is a substrate for the 3-hydroxylase. The 3'-hydroxylase is localized in the microsomal fraction and requires NADPH as cofactor. Naringenin and dihydro-kaempferol but not 4-coumarate or 4-coumaroyl-CoA are substrates for this enzyme. 3'-Hydroxylase activity is present only in genetic lines of M. incana with the wild-type allele b⁺.