β-Amylases are exo-enzymes, which attack amylose chains resulting in efficient successive removal of maltose units from the non-reducing end. In the case of amylopectin, the cleavage stops two to three glucose units from the α-1,6-branching points. β-amylase is used for the production of maltose syrups and in breweries for adjunct processing. The most important commercial products are made from barley or soybeans. Spezyme®BBA 1500, from Genencor International, is a barley α-1,4-D glucan maltohydrolase and is commonly referred to as β-amylase. It is extracted from barley grain. β-Amylase is an exoamylase that catalyzes the release of successive maltose units by hydrolyzing α-1,4-D glycosidic linkages from the non-reducing end of the dextrin chain. The enzyme is free of a-amylase activity, therefore virtually no glucose is formed.
A purified maltogenic amylase (MaltogenaseTM) is produced by Novo Nordisk from a genetically modified strain of Bacillus subtilis (host), which has received the gene for maltogenic amylase from a strain of Bacillus stearothermophillus (donor).
Maltogenase is a maltogenic amylase (exo), which hydrolyses α-1,4-glycosidic linkages from the non-reducing end of the maltodextrin chain. Maltodextrins, oligosaccharides and maltotriose are hydrolysed mainly to maltose. Maltogenase is available in liquid form with a standardized activity of 4000 MANU g-1. One MANU (Maltogenic Amylase Novo Unit) is the amount of enzyme which under standard conditions hydrolyses one micromole of maltotriose per min at 37°C, pH 5.0. The substrate concentration under standard conditions is 10 g maltotriose/1.