| Abstract: | The aim was to identify the mechanism(s) responsible for the release of bound β‐amylase in soluble forms in vitro and during the germination of barley. Preparations of bound β‐amylase, from barley, were treated with different agents including papain, thiols, starchy endosperm extract and reagents with amphipathic characteristics. The time courses of the release of the bound enzyme were compared using the different releasing agents. All the reagents tested caused some release of bound β‐amylase. Probably a very complex combination of mechanisms is involved in the release of bound β‐amylase as barley germinates. Initial release may be by cleavage of disulphide bonds which bind β‐amylase to insoluble protein. Material having amphipathic characteristics may break hydrophobic associations between β‐amylase and insoluble protein(s). The larger molecular weight isoforms are proteolysed to form the lower molecular weight materials present in malt. Limited proteolysis may also occur before the release of bound enzyme. Whether or not proteolysis is directly responsible for the release of bound enzyme remains uncertain. |
