Cytochromes P-450 catalyze the formation of marchantins A and C in Marchantia polymorpha

Abstract Two specific cytochrome P-450 enzymes were detected in cell suspension cultures of Marchantia polymorpha ; the first catalyzes the coupling of two molecules of lunularic acid to form marchantin C and CO 2 and the second hydroxylates marchantin C to marchantin A. Cell free experiments using 3 H / 14 C doubly-labeled substrates demonstrated that lunularic acid, and neither lunularine nor prelunularic acid, is the sole substrate for the coupling reaction. Both enzymes are dependent on the presence of oxygen and NADPH. Both reactions were inhibited in the presence of CO in the dark; this inhibition was partially reversed by white light. In addition, both reactions were inhibited by typical inhibitors of cytochrome P-450 enzymes such as cytochrome c and ancymidol.