Description
A heme-thiolate protein (P-450). The 3',5'-dihydroxyflavanone is formed via the 3'-hydroxyflavanone. In Petunia hybrida the enzyme acts on naringenin, eriodictyol, dihydroquercetin (taxifolin) and dihydrokaempferol (aromadendrin). The enzyme catalyses the hydroxylation of 5,7,4'-trihydroxyflavanone (naringenin) at either the 3' position to form eriodictyol or at both the 3' and 5' positions to form 5,7,3',4',5'-pentahydroxyflavanone (dihydrotricetin). The enzyme also catalyses the hydroxylation of 3,5,7,3',4'-pentahydroxyflavanone (taxifolin) at the 5' position, forming ampelopsin. NADH is not a good substitute for NADPH.
Reaction
a flavanone + 2 NADPH + 2 H+ + 2 O2 = a 3',5'-dihydroxyflavanone + 2 NADP+ + 2 H2O (overall reaction); (1a) a flavanone + NADPH + H+ + O2 = a 3'-hydroxyflavanone + NADP+ + H2O; (1b) a 3'-hydroxyflavanone + NADPH + H+ + O2 = a 3',5'-dihydroxyflavanone + NADP+ + H2O