In enzymology, a reticuline oxidase is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are (S)-reticuline and O2, whereas its two products are (S)-scoulerine and H2O2. This enzyme belongs to the family of oxidoreductases, specifically those acting on X-H and Y-H to form an X-Y bond with oxygen as acceptor. The systematic name of this enzyme class is (S)-reticuline:oxygen oxidoreductase (methylene-bridge-forming). Other names in common use include BBE, berberine bridge enzyme, berberine-bridge-forming enzyme, and tetrahydroprotoberberine synthase. This enzyme participates in alkaloid biosynthesis i.