STUDIES ON ENZYMES PRODUCED BY BACILLUS .3. PURIFICATION AND SOME PROPERTIES OF A PROTOPECTIN-SOLUBILIZING ENZYME THAT HAS POTENT ACTIVITY ON SUGAR-BEET PROTOPECTIN

We found a novel protopectin-solubilizing enzyme that had potent activity on the protopectin in sugar beet pulp, in the culture filtrate of Bacillus subtilis IFO 3134. The enzyme was purified by treatment with EDTA and chromatography on CM-Cellulofine CH, Butyl-Toyopearl 650, and Toyopearl HW-55S, and was isolated as a homogeneous protein. The enzyme had an apparent molecular weight of 30,000 in SDS-polyacrylamide gel electrophoresis, and 27,000 in permeation chromatography on Toyopearl HW-55S, with its isoelectric point around pH 9.0. The enzyme was stable from pH 5.0 to 9.0 and up to 60°C. The optimum pH for enzyme action was 6.0 at 37°C and pH 8.0 at 60°C. The enzyme catalyzed the release of pectin from protopectin of various citrus fruit peels as well as sugar beet pulp, but much less from that of lemon peel, without catalyzing the degradation of polygalacturonic acid. The enzyme catalyzed the degradation of arabinan in sugar beet pulp, and it seemed to release pectin by splitting the arabinan connecting the pection to cell wall polysaccharides. © 1990 by the Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.