Figure 1

A simplified version of a section of the flavonoid biosynthetic pathway. The flavonols kaempferol, quercetin and myricetin are formed from dihydrokaempferol, dihydroquercetin and dihydromyricetin, respectively, by flavonol synthase (FLS). The double arrows show the points of possible action of multiple enzymes for formation and modification of the anthocyanins. Abbreviations are as follows: CHS, chalcone synthase; CHI, chalcone isomerase; F3H, flavanone 3-hydroxylase; DFR, dihydroflavonol 4-reductase; ANS, anthocyanidin synthase; F3'H, flavonoid 3'-hydroxylase; F3'5'H, flavonoid 3',5'-hydroxylase; F3GT, flavonoid 3-O-glucosyltransferase; A5GT, anthocyanin 5-O-glucosyltransferase; A3'OMT, anthocyanin 3'-O-methyltransferase; A3'5'OMT, anthocyanin 3',5'-O-methyltransferase. The numbering of the 3', 4' and 5' carbon positions is shown on the anthocyanin structure.