brassinolide synthase activity
Catalysis of the reaction: castasterone + O2 + reduced [NADPH--hemoprotein reductase] = brassinolide + H+ + H2O + oxidized [NADPH--hemoprotein reductase]. Broad specificity for several brassinosteroids, including castasterone, teasterone, and typhasterol.
GO:0016712
oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
is_a