CONVERSION OF EMODIN TO CHRYSOPHANOL IN A CELL-FREE SYSTEM FROM PYRENOCHAETA TERRESTRIS

Article abstract of DOI:10.1016/S0031-9422(00)94510-2

Incubation of a cell-free extract from Pyrenochaeta terrestris with <3H>emodin gave a single major product which was purified and identified as chrysophanol by mass spectrometry.Maximum conversion of <3H>emodin to <3H>chrysophanol was obtained with anaerobic conditions and NADPH, ATP, mercaptoethanol, iron(II) and glycerol.The apparent K_m for emodin in the crude extract was 1.0 +/- 0.2 μM.At 4.2 μM, the conversion of emodin was 17 times the conversion of emodinanthrone to chrysophanol plus chrysophanolanthrone.It is proposed that chrysophanol is synthesized in plant and fungal species primarily by dehydroxylation of emodin.Key Word Index-Pyrenochaeta terrestris; Sphaeropsidaceae; cell-free system; biosynthesis; emodin; chrysophanol