Most glucoamylases (a-1,4-d-glucan glucohydrolase, EC ) have structures consisting of both a catalytic and a starch binding domain. The structure of a glucoamylase from Saccharomycopsis fibuligeraHUT 7212 (Glu), determined a few years ago, consists of a single catalytic domain. The structure of this enzyme with the resolution extended to A˚ and that of the enzyme–acarbose complex at A˚ resolution are presented here.