Alpha-glucosidase II (alpha-D-glucoside glucohydrolase) is a glycosyl hydrolase family 31 (GH31) enzyme, found in bacteria and plants, which has exo-alpha-1,4-glucosidase and oligo-1,6-glucosidase activities. Alpha-glucosidase II has been characterized in Bacillus thermoamyloliquefaciens where it forms a homohexamer. This subgroup also includes the MalA alpha-glucosidase from Sulfolobus solfataricus and the AglA alpha-glucosidase from Picrophilus torridus. MalA is part of the carbohydrate-metabolizing machinery that allows this organism to utilize carbohydrates, such as maltose, as the sole carbon and energy source.