Biochemical characterization of purified lipoxygenase from sesame (Sesamum indicum)

Abstract

A 66.3 kDa lipoxygenase (LOX) with optimum pH of 8.0 and temperature of 35 °C was purified from Sesamum indicum. Fe2+and Ca2+ could stimulate the enzyme activity by 160 and 141%, respectively, while Co2+ highly reduced it to 20%. The LOX activity was decreased at 1.5 mM of cetyltrimethylammonium bromide (CTAB) and β-mercapto ethanol, and 2.5 mM of phenylmethylsulfonyl fluoride (PMSF) and ethylenediaminetetraacetic acid (EDTA). The enzyme showed Km = 1.01 μM and Vmax = 0.054 μmol.min−1 toward linoleic acid as the substrate. The IC50 values for LOX inhibitors including potassium cyanide (KCN) (270 µM), β-carotene (48 µM), and ascorbic acid (132 µM) were determined.