Exo-type enzymes that sequentially degrade starch, removing units of beta-glucose from the non-reducible end of starch molecules. Also known as amyloglucosidase, s-amylase, saccharifying amylase and the diastatic enzyme.   Produced solely by micro-organisms.

Most can act on not only the alpha-1,4 glycosidic bond but also the alpha-1,6 glycosidic bond. As they thus have very high decompositional capacity, some have the ability (like enzymes from the Rhizopus genus) to degrade starch to glucose to almost 100%.

When measuring this enzyme, it is necessary to keep the influence of the co-existing α-amylase to a minimum. The sample is made to react with the starch substrate, and the amount of glucose produced is measured.

The production capacity of glucoamylase in koji used in sake making is generally 100-300mg of glucose per gramme of koji per hour.

This enzyme is held to be the main constituent of protein cloudiness (tanpaku kondaku) in seishu.