Functions as flavone synthase II (FNSII) that catalyzes the direct conversion of flavanones to flavones (PubMed:20132953). In vitro, can convert liquiritigenin, naringenin and eriodictyol to 7,4'-dihydroxyflavone, apigenin and luteolin, respectively (PubMed:20132953). a flavanone + O2 + reduced [NADPH--hemoprotein reductase] = a flavone + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] Optimum pH is 7.9. Optimum temperature is 25 degrees Celsius. Secondary metabolite biosynthesis; flavonoid biosynthesis. Belongs to the cytochrome P450 family.