Glucan 1,4-alpha-glucosidase (glucoamylase; <db_xref db="EC" dbkey="3.2.1.3"/>) catalyses the release of glucose from the non-reducing ends of starch and related polysaccharides. Smaller molecular forms of the enzyme, G2, arise by proteolytic cleavage(s) of the carboxyl end of the large form, G1. Only G1 adsorbs and digests raw starch, but both forms are equally active towards soluble poly- and oligosaccharides [<cite idref="PUB00011143"/>]. The majority of these enzymes are multidomain proteins consisting of a catalytic domain connected to a starch-binding domain (SBD) by an O-glycosylated linker region. Glu179 and Glu400 of the the <taxon tax_id="5061">Aspergillus niger</taxon> sequence is involved in the general acid catalysis of the enzyme. Conserved tryptophan residues are involved in interactions of the glucoamylases with substrates and inhibitors [<cite idref="PUB00011144"/>]. Glucan 1,4-alpha-glucosidase, starch-binding