Purification and some properties of African oil bean seed lipoxygenase--Part 1.

Lipoxygenase was extracted from African oil bean seed and purified by ammonium sulphate precipitation, gel filtration on Sephadex G-25 and ion-exchange chromatography on DEAE--cellulose column. The enzyme was purified 79.63 fold and 36% of the enzyme activity was recovered. The molecular weight of the enzyme was 102,000 daltons and the peroxide value was 10.56 x 10(-3) mM. The Vmax was 0.14 OD min-1 while the Km value was 1.92 x 10(-4) M. The enzyme had an optimum pH of 7.0 and optimum temperature of 30 degrees C. While diethyl-dithiocarbamate was the best inhibitor of the enzyme's oxidation of linoleic acid, nordihydroguiaretic acid was the best antioxidant for its oxidation of the fatty acid. African oil bean seed lipoxygenase had high enzyme activity of 86% when compared to soybean lipoxygenase (considered to be the best source of the enzyme). This means that African oil bean seed is a good source of lipoxygenase for biotechnology such as the bleaching of browned yam tubers.