Isolation of phospholipase A2 from soybean (Glycine max) seeds: the study of its enzymatic properties.

摘要

A phospholipase A2 (PLA2) with potential use for production of surfactants for the food industry was purified from soybeans using affinity chromatography and characterized. The enzyme was found have a mol. wt. of 14 kDa and showed activity against liposomes. Using soybean phospholipids as substrate the PLA2 showed selective hydrolysis at the sn-2 position. Activity required millimolar concn. of Ca2+ and was optimum at slightly alkaline pH values. The PLA2 was inhibited by ammonium sulfate and stimulated by auxins. It was classified as a secretory PLA2 due to its inhibition by p-bromo-phenacyl bromide. The enzyme showed good thermal stability and resistance to the presence of organic solvents. Lipolytic activity against multlamellar vesicles and a water-in-oil microemulsion was demonstrated. Vmax and Km for the former activity were 950 U/mg and 0.78mM. PLA2-catalysed lipolysis of the emulsion generated lysoderivative biosurfactants.