Purification and Properties of Lipoxygenase-like Enzyme from a Red Alga, Porphyra yezoensis

Abstract

Lipoxygenase-like enzyme was purified 17-fold in a yield of 15% from crude enzyme extract of a red alga Porphyra yezoensis to near homogeneity by heat treatment, stepwise elution with DE-52 cellulose and a Sephadex G-75 gel filtration column chromatography. The final preparation showed a single band with polyacrylamide gel electrophoresis, and its specific staining for lipoxygenase activity existed on the same site. The estimated specific activity of the purified enzyme was 34.4μmol/min per mg protein, using linoleic acid as a substrate. The purified enzyme had a pH optimum of pH 9 and was found to be highly resistant to heat treatment. The activity of the purified enzyme was inhibited by hydrogen peroxide, but not by cyanide and EDTA. The purified enzyme had a higher specificity for linoleic acid. It was assumed from the results that the enzyme purified from Porphyra yezoensis is closer to a lipoxygenase and not a hematin compound.