PARTIAL PURIFICATION AND PROPERTIES OF PUMPKIN LIPOXYGENASE WITH CAROTENE-BLEACHING ACTIVITY |
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Authors: | TOSHIRO HIDAKA SUNAO KATSUKI YASUO NAGATA SEIICHIRO NAKATSU |
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Affiliation: | Department of Agricultural Chemistry Faculty of Agriculture Miyazaki University Miyazaki, 889-21 Japan |
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Abstract: | From locally grown pumpkins, an active lipoxygenase preparation with an active carotene-bleaching factor was partially purified by ammonium sulfate fractionation, gel filtration, and ion-exchange chromatography. The enzyme had a pH optimum at 6.5 and was inactive at pH below 3 and above 10. The maximum activity occurred at 30°C. The apparent Km determined in the presence of linoleate was 0.33 × 10?3 M. The heavy metals Hg2+, Cu2+, Co2+, and Fe3+ were effective inhibitors of this enzyme. Cyanide, fluoride, and L-ascorbic acid also inhibited lipoxygenase activity. Carotene-bleaching activities operated strongly on the lipoxygenase fraction and slightly on the denatured lipoxygenase and hemoproteins treated with heat. |
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