Isozymes of the Glycolytic Enzymes in Endosperm from Developing Castor Oil Seeds

Abstract

Ion filtration chromatography on diethylaminoethyl-Sephadex A-25 has been used to separate two isozymes each of triose phosphate isomerase, glyceraldehyde 3-phosphate dehydrogenase, glycerate 3-phosphate kinase, enolase, and phosphoglycerate mutase from homogenates of developing castor oil (Ricinus communis L. cv. Baker 296) seeds. Crude plastid fractions, prepared by differential centrifugation, were enriched in one of the isozymes, whereas the cytosolic fractions were enriched in the other. These data (and data published previously) indicate that plastids from developing castor oil seeds have a complete glycolytic pathway and are capable of conversion of hexose phosphate to pyruvate for fatty acid synthesis. The enzymes of this pathway in the plastids are isozymes of the corresponding enzymes located in the cytosol.