Alpha amylase is classified as family 13 of the glycosyl hydrolases. The structure is an 8 stranded alpha/beta barrel containing the active site, interrupted by a ~70 a.a. calcium-binding domain protruding between beta strand 3 and alpha helix 3, and a carboxyl-terminal Greek key beta-barrel domain.

1: Refined molecular structure of pig pancreatic alpha-amylase at 2.1 A resolution. Larson SB, Greenwood A, Cascio D, Day J, McPherson A; J Mol Biol 1994;235:1560-1584. PMID:8107092

2: Crystal structure of yellow meal worm alpha-amylase at 1.64 A resolution. Strobl S, Maskos K, Betz M, Wiegand G, Huber R, Gomis-Ruth FX, Glockshuber R; J Mol Biol 1998;278:617-628. PMID:9600843