(S)-Tetrahydroberberine oxidase (EC 1.3.3.8) is an enzyme that catalyzes the final transformation in the biosynthesis of berberine, a quaternary benzylisoquinoline alkaloid of the protoberberine structural subgroup.[1][2] This reaction pathway catalyzes the four-electron oxidation of (S)-tetrahydroberberine (also known as (S)-canadine) in the presence of oxygen to produce berberine and hydrogen peroxide as products.
This enzyme belongs to the family known as oxidoreductases, in this instance the CH-CH moiety acts as the electron donor with oxygen acting as the electron acceptor. The systematic name of this enzyme is (S)-tetrahydroberberine:oxygen oxidoreductase; but it is also known as (S)-THB oxidase, tetrahydroberberine oxidase, and decreasingly, as (S)-tetrahydroprotoberberine oxidase.[3][4]
^Amann M, Nagakura N, Zenk MH (1984). "(S)-tetrahydroprotoberberine oxidase the final enzyme in protoberberine biosynthesis". Tetrahedron Lett. 25 (9): 953–4. doi:10.1016/S0040-4039(01)80071-X.
^Okada N, Shinmyo A, Okada H, Yamada Y (1988). "Purification and characterization of (S)-tetrahydroberberine oxidase from cultured Coptis japonica cells". Phytochemistry. 27 (4): 979–82. doi:10.1016/0031-9422(88)80255-3.
