Studies on lipoxygenase from rice bran

Abstract

Unfractionated rice bran extract showed on disc-gel electrophoresis three distinct bands with lipoxygenase activity. The major fraction was partially purified by repeated ammonium sulfate fractionation at pH 6.8. The partially purified lipoxygenase was optimally active at pH 8.5 and had a Km of 0.35 mM using linoleate as a substrate. It was stable for 15 days at 3 to 5 C. The enzyme activity was not affected by alpha, alpha prime-dipyridyl and EDTA but partially by 1,10-phenanthroline. Ferrous and calcium ions were activators but copper ions were inhibitory. The enzyme may require tryptophan residues for activity.