A process for converting starch or partially hydrolyzed starch into a syrup containing dextrose includes the steps of saccharifying starch hydrolyzate in the presence of a saccharifying starch hydrolyzate in the presence of a mutated glucoamylase or related enzyme and increasing the selectivity of the enzyme for α-(1→4)-glucosidic bonds by the glucoamylase or related enzyme by including at least one mutation, the mutation substituting an amino acid of the enzyme with at least one amino acid chosen by comparison with structurally related regions of other enzymes that selectively hydrolyze only α-(1→4) glucosidic bonds. Enzymes made in accordance with the present invention are also disclosed
