Hydrolysis of terminal (1->4)-linked alpha-D-glucose residues successively from non-reducing ends of the chains with release of beta-D-glucose. Rhizopus glucoamylase exists in multiple forms, Gluc 1, Gluc 2, and Gluc 3, all of which hydrolyze gelatinized starch at similar rates, but only the largest one (Gluc 1) is able to adsorb raw starch. Glucoamylase 3 may be 110-604 instead of 116-604. Belongs to the glycosyl hydrolase 15 family.