Purification and some properties of alkaline pullulanase from a strain of bacillus no. 202-1, an alkalophilic microorganism

Pullulanase (pullulan 6-glucanohydrolase EC 3.2.1.41) was purified about 290-fold from the culture fluid of Bacillus No. 202-1 by DEAE-cellulose adsorption, acetone fractionation, (NH4) 2SO4 precipitation and DEAE--cellulose column chromatography followed by Sephadex G-200 molecular sieve chromatography. The enzyme gave a single band of protein by disc polyacrylamide gel electrophoresis. The molecular weight was estimated as 92 000 by sodium dodecyl sulfate gel electrophoresis. The isolectric point was lower than pH 2.5. The optimum pH for enzyme action was about 8.5-9.0. The action of the enzyme on amylopectin and glycogen resulted in increase in the iodine coloration of 85% and 70%, respectively. The enzyme completely hydrolyzed 1,6-alpha-glucosidic linkages in amylopectin, glycogen and pullulan.

The limit dextrinases from ungerminated oats (Avena sativa L.) and ungerminated rice (Oryza sativa L.)

The limit dextrinases from ungerminated oats and rice have been purified, and their substrate specificity compared with a bacterial isoamylase preparation. Both cereal enzymes could hydrolyse (1 yields6)-alpha-D-glucosidic linkages in oligosaccharide alpha-dextrins, pullulan, amylopectin, and the beta-limit dextrins of amylopectin and glycogen. However, under comparable conditions, they were unable to attack glycogens.