Accepted name: psoralen synthase
Reaction: (+)-marmesin + [reduced NADPH—hemoprotein reductase] + O2 = psoralen + [oxidized NADPH—hemoprotein reductase] + acetone + 2 H2O
Glossary: (+)-marmesin = (S)-2-(2-hydroxypropan-2-yl)-2,3-dihydro-7H-furo[3,2-g]chromen-7-one
psoralen = 7H-furo[3,2-g]chromen-7-one
Other name(s): CYP71AJ1
Systematic name: (+)-marmesin,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase
Comments: This microsomal cytochrome P-450 (heme-thiolate) enzyme is rather specific for (+)-marmesin, although it can also accept 5-hydroxymarmesin to a much lesser extent. Furanocoumarins protect plants from fungal invasion and herbivore attack. (+)-Columbianetin, the angular furanocoumarin analogue of the linear furanocoumarin (+)-marmesin, acts as a competitive inhibitor even though it is not a substrate.
1.  Larbat, R., Kellner, S., Specker, S., Hehn, A., Gontier, E., Hans, J., Bourgaud, F. and Matern, U. Molecular cloning and functional characterization of psoralen synthase, the first committed monooxygenase of furanocoumarin biosynthesis. J. Biol. Chem. 282 (2007) 542–554. [PMID: 17068340]
[EC created 2007 as EC, transferred 2018 to EC]