Purification and Characterization of Extracellular β-Galactosidase Secreted by Supension Cultured Rice (Oryza sativa L.) Cells

Abstract

  A β-galactosidase was purified 1300-fold by lactosyl-Sepharose 4B and Sephacryl S-200 column chromatographies from the cultured medium of a rice-cell suspension. The purified enzyme appeared as 47 kD and 40 kD polypeptides on SDS-PAGE and had a specific activity of 65.1 units/mg. Optimum activity was observed at pH 3.5 and 60°C. The enzyme released galactose from galactoxyloglucan and pectic galactans.