Purification and Properties of Co²⁺ Requiring Heme Protein Having Lipoxygenase Activity from Fusarium oxysporum

Abstract

Co²⁺ -requiring heme protein having lipoxygenase activity, obtained from Fusarium oxysporum (FUSARIUM lipoxygenase) was extensively purified by ammonium sulfate precipitation, ion exchange chromatography on SP-Sephadex and gel filtration with Sephadex G-100. The final preparation achieved homogeneity by ultracentrifugation and SDS-polyacrylamide gel electrophoresis. The molecular weight was estimated at 12, 000 to 13, 000 on the basis of ultracentrifugation, SDS-polyacrylamide gel electrophoresis and gel filtration. FUSARIUM lipoxygenase contained 1 mole protoheme IX per mole enzyme, required Co²⁺ as a stabilizing factor and lost activity by treatment with heat or proteases. FUSARIUM lipoxygenase-catalyzed oxidation was proved to be differrent from the well-known soybean lipoxygenase-catalyzed oxidation and hemeprotein or cobalt-catalyzed oxidations in various respects including reaction velocity, substrate specificity pI and activation energy.