(7S)-marmesin + reduced [NADPH--hemoprotein reductase] + O2 = psoralen + acetone + oxidized [NADPH--hemoprotein reductase] + 2 H2O + H(+)
(7s)-marmesin + reduced [nadph--hemoprotein reductase] + o2 = psoralen + acetone + oxidized [nadph--hemoprotein reductase] + 2 h2o + h(+)