SEPARATION OF LIPOXYGENASE AND THE MAJOR SOYBEAN PROTEINS USING AQUEOUS 2-PHASE EXTRACTION AND POLY(ETHYLENE GLYCOL) PRECIPITATION SYSTEMS

This paper examines the separation of lipoxygenase and the major proteins in soybeans using aqueous two-pha.se extraction and poly(ethylene glycol) (PEG) precipitation systems. The aqueous two-phase systems were composed of poly(ethylene glycol) and the salt ammonium sulfate. The major proteins examined include glycinin, beta-conglycinin, soybean agglutinin, lipoxygenase, and soybean trypsin inhibitor. Enzymatic activity was used to measure the partitioning and solubility of lipoxygenase. Lipoxygenase was found to partition almost exclusively to the top phase. Solubility of lipoxygenase in poly(ethylene glycol) systema was found to be dependent on ionic strength. High-resolution gel electrophoresis was used to examine the spectrum of proteins present in the top and bottom phases of two-phase systems and the supernatant of PEG systems. The proteins present in the acid-soluble fraction were also examined by two-dimensional gel electrophoresis.