Study of Extracellular and Immobilized Saccharase in Foxglove

Abstract

Cells in suspension culture of foxglove (Digitalis lanata Ehrh.) were permeabilized with Tween 20, Tween 80, ethanol, hexadecyltrimethylammonium bromide or hexadecylpyridinium chloride and immobilized using glutaraldehyde. Saccharase showed a pH optimum at 4.6 and 5.4; the optimum temperature for immobilized cells and for cell suspension culture were 50 °C and 45 °C, respectively. Four-hour hydrolysis of the substrate proceeded with a conversion of 63 %. The immobilized cells showed a high saccharase activity, good stability of plant saccharase in long-term storage and convenient physico-mechanical properties. The culture medium (without cells) was used for identification and determination of extracellular enzyme activity. The intracellular activity of saccharase estimated in cell suspension accounts for 88.4 % of the total activity the rest is due to the extracellular activity. The specific intracellular activity is 4.6 times higher than the extracellular one. The described method permits a rapid, simple and specific identification.