Reaction: a flavanone + 2 [reduced NADPH—hemoprotein reductase] + 2 O2 = a 3',5'-dihydroxyflavanone + 2 [oxidized NADPH—hemoprotein reductase] + 2 H2O (overall reaction)
(1a) a flavanone + [reduced NADPH—hemoprotein reductase] + O2 = a 3'-hydroxyflavanone + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) a 3'-hydroxyflavanone + [reduced NADPH—hemoprotein reductase] + O2 = a 3',5'-dihydroxyflavanone + [oxidized NADPH—hemoprotein reductase] + H2O
For diagram of reaction click here or click here or click here.
Other name(s): flavonoid 3',5'-hydroxylase
Systematic name: flavanone,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (3',5'-dihydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein found in plants. 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.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Menting, J., Scopes, R.K. and Stevenson, T.W. Characterization of flavonoid 3',5'-hydroxylase in microsomal membrane fraction of Petunia hybrida flowers. Plant Physiol. 106 (1994) 633-642. [PMID: 12232356]
2. Shimada, Y., Nakano-Shimada, R., Ohbayashi, M., Okinaka, Y., Kiyokawa, S. and Kikuchi, Y. Expression of chimeric P450 genes encoding flavonoid-3', 5'-hydroxylase in transgenic tobacco and petunia plants1. FEBS Lett. 461 (1999) 241-245. [PMID: 10567704]
3. de Vetten, N., ter Horst, J., van Schaik, H.P., de Boer, A., Mol, J. and Koes, R. A cytochrome b5 is required for full activity of flavonoid 3', 5'-hydroxylase, a cytochrome P450 involved in the formation of blue flower colors. Proc. Natl. Acad. Sci. USA 96 (1999) 778-783. [PMID: 9892710]