Interaction between chloroplast pigments and lipoxygenase enzymatic extract of olives

Lipoxygenase activity in olive fruits increases considerably when the enzym e is extracted using extraction buffer with ethylenediaminetetraacetate, Tr iton X-100, dithiothreitol, sodium metabisulfite, and hydrated polyvinylpol ypyrrolidone. In the absence of these compounds the activity measured of th e crude extract is almost negligible, and further effects of the enzymatic reaction, such as bleaching activity on chloroplast pigments, do not appear . Moreover, when the oxidizing level of the medium is increased by the addi tion of linoleic acid or soybean lipoxygenase with linoleic acid, the crude enzymatic extracts of olives reduce the destructive capacity of soybean li poxygenase on chlorophylls to one-sixth. These results suggest a double pig ment protection against lipoxygenase in the olive crude extract, one inhibi ting the enzyme and the other interrupting the chain of oxidative reactions beginning with hydroperoxide formation.