Abstract
Glucoamylases (EC 3.2.1.3) (GA) from Rhizopus sp. strain Fukumoto could be separated into several forms by Ampholine isoelectric focusing (IEF) and by gel filtration on Sephadex G-50. Their isoelectric points separated by IEF were 6.7, 7.4, 7.9, 8.3 and 8.7, and they were designated as GA-6.7, GA-7.4, GA-7.9, GA-8.3 and GA-8.7, respectively. Among them, GA-7.9 and GA-8.3 were the main constituents of GA and each of them was separated further to two forms by gel filtration on Sephadex G-50, and they were designated as GA-7.9 I, GA-7.9 II, GA-8.31 and GA-8.3 II, in the order eluted from the column. GA-7.9 II and GA-8.3 II digested raw starch from potato more rapidly than GA-7.9 I and GA-8.3 I, respectively. But the mobility of GA-7.9 I coincided with that of GA-7.9 II, and the mobility of GA-8.3 I did with that of GA-8.3 II in polyacrylamide gel electrophoresis at pH 4.0. Their molecular weights were all approximately 53, 000 by SDS-polyacrylamide gel electrophoresis.
