Enables glucan 1,3-alpha-glucosidase activity. Involved in N-glycan processing. Part of glucosidase II complex. Is expressed in several structures, including alimentary system; genitourinary system; heart; nervous system; and sensory organ. Human ortholog(s) of this gene implicated in polycystic kidney disease; polycystic kidney disease 3; and polycystic liver disease. Orthologous to human GANAB (glucosidase II alpha subunit). [provided by Alliance of Genome Resources, Apr 2022]