Characterization and Subcellular Localization of Debranching Enzyme and Endoamylase from Leaves of Sugar Beet

摘要: Sugar beet leaves (Beta vulgaris L.) contained up to five endoamylases, two exoamylases, and a single debranching enzyme. Four of the endoamylases enzyme were present in chloroplast. The chloroplastic starch-debranching an apoplastic endoamylase copurified from mature sugar by 35 50% ammonium sulfate precipitation chromatography on diethylaminoethyl-Sephacryl, beta-cyclodextrin Sepharose 6B, Sephadex G-150. enzyme, which was purified homogeneity, had molecular mass 100 kilodaltons pH optimum 5.5. It showed high activity with pullulan as substrate, low soluble starch amylopectin, no native grains isolated leaves. endoamylase, partially purified, 43,000 kilodaltons, 6.5, required calcium for thermal stability, ability hydrolyze grains.