FIGURE 2. Flavonoid biosynthetic pathway. Enzymes involved in anthocyanin biosynthesis and side branches leading to related flavonoid pathways are shown. PAL, phenylalanine ammonialyase; C4H, cinnamate 4-hydroxylase; 4Cl, coumarate: CoA ligase; CHS, chalcone synthase; CHI, chalcone isomerase; F3H, flavanone 3β-hydroxylase; F3′H, dihydroflavonol 3′ hydroxylase; F3′5′H, dihydroflavonol 3′5′ hydroxylase; DFR, dihydroflavonol reductase; ANS, anthocyanidin synthase; UF3GT, UDP-glucose flavonol 3-0-glucosyl transferase; RT, rhamnosyl transferase.