DIOXYGENATION OF LONG-CHAIN ALKADIEN(TRIEN)YLPHENOLS BY SOYBEAN LIPOXYGENASE

Long-chain alkadien(trien)ylphenols, i.e., cardanols, cardols, and ana cardic acids, as well as their acetylated and methylated derivatives w ere used in enzymatic dioxygenation catalyzed by soybean lipoxygenase- 1 (LOX-1). Kinetic studies revealed the influence of functional groups , chain length, number of double bonds, and the distance of the double bonds from the terminal end. Free functional groups were found to be a structural prerequisite for high affinity and turnover number; excep tional kinetic parameters were obtained for omega-6 compounds possessi ng the same chain length as linoleic acid. The regioselectivity and en antioselectivity of LOX-1 catalysis were investigated with 3-[(Z,Z)-8' ,11'-pentadecadienyl]phenol as the representative substrate, yielding S)-hydroperoxy-(Z,E)-8',10'-pentadecadienyl]phenol as the main product , Our extensive chromatographic and spectroscopic studies comprised HP LC-MS/MS for differentiation of the regioisomers, H-1 NMR spectroscopy for determination of the double-bond configuration, GC-MS to evaluate the enantiomeric excess, and exciton-coupled circular dichroism for d etermination of the absolute configuration.