Free and Protein‐bound β‐Amylases of Barley Grain. Characterization by Two‐dimensional Immunoelectrophoresis

Abstract

AbstractThe β‐amylases of ungerminated barley (Hordeum distichum L. cv. Emir) were characterized by two‐dimensional immunoelectrophoretic techniques in order to elucidate the structure and physiological importance of the latent β‐amylase present in cereal grains. Two water‐soluble forms with partial immunochemical identity were detected. One of the enzyme forms was found to consist of aggregates between β‐amylase and an immunochemically distinct non‐active protein. Both β‐amylase and the protein could be released from the aggregates with β‐mercaptoethanol and, to some extent, with papain. β‐Mercaptoethanol increased the extractability of β‐amylase and of the non‐active protein. The aggregated form of β‐amylase was found to predominate in extracts made in the presence of papain. Possible functions of the non‐enzymatic protein in formation of latent β‐amylase is discussed.