Fig 4.
Reactions involved in GA inactivation, acting on C19-GAs (A) or C20-GAs (B). Different enzyme types are indicated by color: brown, 2-oxoglutarate-dependent dioxygenases; green, cytochrome P450s (enzymes present in rice in dark green and in Arabidopsis light green); red, methyltransferases; blue, glucosyltransferases; and purple, epoxide hydrolase. GA12 13-hydroxylation, which initiates the biosynthesis of GA1, results in slight reduction in bioactivity and is consequently included in (B). The involvement of EUI2 in dihydrodiol formation is assumed, but has not been demonstrated.