KIWIFRUIT LIPOXYGENASE - PREPARATION AND CHARACTERISTICS

Kiwifruit were analyzed for the presence of lipoxygenase (LOX) after mass-spectrophotometric analysis of kiwifruit pulp showed the presence of hexanal and hex-2-enal, considered to be break-down products of the reaction initiated by LOX. A spectrophotometric assay showed high levels of LOX when compared to other fruits and vegetables. Kiwifruit have at least one isoenzyme belonging to the class II group of LOX iso-enzymes, similar to those identified in asparagus, cucumber, tomato and apple. The LOX required detergent-solubilization and was partially purified. Relative to other known lipoxygenases kiwifruit LOX is heat-stable. It catalysed the hydroperoxidation of free fatty acids but not trilinolein.