Biocatalysis of lipoxygenase in selected organic solvent media

The biocatalysis of purified soybean lipoxygenase (LOX) (EC 1.13.11.12), using linoleic acid as a substrate model, was investigated in selected organic solvent media, including chloroform, dichloromethane, hexane, iso-octane, octane and toluene. The results indicated that there was a 2.6-fold increase in LOX activity in the monophasic iso-octane medium compared to that obtained in the aqueous medium. The results also showed that there was an increase of 2.2- and 1.8-fold in LOX activity in the monophasic reaction media of octane and hexane, respectively. However, an inhibitory effect on enzyme activity was observed when the monophasic reaction media of toluene, chloroform and dichloromethane were used. In addition, the results showed that the optimum concentration of octane and iso-octane in the biphasic medium containing the organic solvent and Tris–HCl buffer solution, was determined to be 3.5% and 4%, respectively, for LOX activity. Moreover, the biocatalysis of LOX in a ternary micellar system, containing either 3.5% octane or 4% iso-octane, Tris–HCl buffer solution and an emulsifier, resulted in an overall increase in enzyme activity. The Km and Vmax values, substrate specificity, optimum protein concentration, optimum reaction temperature as well as the enzymatically catalyzed end-products were investigated for LOX biocatalysis in both ternary micellar systems.