Figure 1.

Simplified scheme of the flavonoid pathway. Representative reactions of each of the major pathway branches are shown. End products are indicated in boldface uppercase letters, and the enzymes catalyzing each step are in uppercase letters. Dotted arrows indicate multiple steps and unidentified enzymes. ANS, Anthocyanidin synthase; CHS, chalcone synthase; CHI, chalcone isomerase; DFR, dihydroflavonol 4-reductase; F3′H, flavonoid-3′-hydroxylase; FLS, flavonol synthase; FNR, flavanone 4-reductase.