BACTERIAL EXPRESSION OF THE BIFUNCTIONAL ALPHA-AMYLASE SUBTILISIN INHIBITOR FROM BARLEY/

The bifunctional alpha-amylase/subtilisin inhibitor (BASI) is an endog enous inhibitor of the high pi cereal alpha-amylases encoded by the am yl genes. Evaluation of the potential role of this protein in malting and brewing would be greatly assisted by the availability of large qua ntities of the protein. We have produced the protein by expression of the barley gene in bacteria. The barley gene was cloned into a pMAL ve ctor and expressed as a fusion protein. The purified fusion protein wa s successfully cleaved with a specific protease to release the native BASI protein. The BASI produced by bacterial expression will be a usef ul source of the protein for studies of interactions with barley alpha -amylases and studies of the influence of this protein on malting and brewing.