Lipoxygenase Activity in Pig Muscle: Purification and Partial Characterization

Lipoxygenase from Iberian pig Biceps femoris muscle was purified in a process that involves two successive chromatographic steps on DEAE-Sephadex and phenyl-Sepharose CL4B. The purified enzyme had a final specific activity of 52 mU/mg, a purification factor of 3250, a molecular weight of 90 kDA, and a maximum activity at pH 5.5. The KM values obtained for linoleic acid (KM = 0.28 mM), arachidonic acid (KM = 3.8 mM), and linolenic acid (KM = 0.43 mM) reveal a preferential use of linoleic acid as substrate. When purified enzyme was incubated in the presence of linoleic acid, two main products were identified by direct-phase HPLC: 9-hydroperoxy octadecadienoic acid and 13-hydroperoxy octadecadienoic acid in the ratio of 45:55. The presence of lipoxygense activity suggest a possible participation of this enzyme in the biogenesis of flavor and aroma in hams from Iberian pigs. Keywords: Lipoxygenase; purification; hams; Iberian pig; lipid oxidation