InterPro domain: IPR000165

This entry represents glucoamylase (GA), also known as glucan 1,4-alpha-glucosidase, which belongs to family 15 ( GH15 ) in the classification of glycosyl hydrolases.

GA catalyses the release of D-glucose from the non-reducing ends of starch and other oligo- or poly-saccharides. Studies of fungal GA have indicated 3 closely-clustered acidic residues that play a role in the catalytic mechanism [ 1 ]. This region is also conserved in a recently sequenced bacterial GA [ 2 ].

The 3D structure of the pseudo-tetrasaccharide acarbose complexed with glucoamylase II(471) from Aspergillus awamori var. X100 has been determined to 2.4A resolution [ 3 ]. The protein belongs to the mainly-alpha class, and contains 19 helices and 9 strands.

1. Catalytic mechanism of fungal glucoamylase as defined by mutagenesis of Asp176, Glu179 and Glu180 in the enzyme from Aspergillus awamori. Protein Eng. 3, 193-8
2. Molecular cloning of a glucoamylase gene from a thermophilic Clostridium and kinetics of the cloned enzyme. Eur. J. Biochem. 207, 413-8
3. Refined structure for the complex of acarbose with glucoamylase from Aspergillus awamori var. X100 to 2.4-A resolution. J. Biol. Chem. 269, 15631-9