Glucoamylase that hydrolyzes alpha-1,4-glucosidic linkages, alpha-1,6-, alpha-1,3- and alpha-1,2-glucosidic linkages during starch degradation. Hydrolysis of terminal (1->4)-linked alpha-D-glucose residues successively from non-reducing ends of the chains with release of beta-D-glucose. Binds 1 Ca(2+) ion per subunit. kcat is 182 sec(-1) for maltose. kcat is 270 sec(-1) for maltotriose. kcat is 321 sec(-1) for maltotetraose. kcat is 434 sec(-1) for maltopentaose. kcat is 346 sec(-1) for maltohexaose. kcat is 381 sec(-1) for maltoheptaose. kcat is 321 sec(-1) for amylose DP17. kcat is 115 sec(-1) for soluble starch. kcat is 141 sec(-1) for kojibiose. kcat is 207 sec(-1) for nigerose. kcat is 105 sec(-1) for isomaltose. kcat is 160 sec(-1) for panose. kcat is 161 sec(-1) for p-nitrophenyl alpha-glucoside. Optimum pH is 6.5. Glycan degradation; starch degradation. Monomer. Belongs to the glycosyl hydrolase 97 family. Although initially defined as an alpha-glucosidase, it produces beta-glucose by an inverting mechanism, suggesting it rather acts as a glucan 1,4-alpha-glucosidase.