Cereal Chem. 71:610-617   |  VIEW ARTICLE


Limit Dextrinase from Malted Barley: Extraction, Purification, and Characterization.

A. W. MacGregor, L. J. Macri, S. W. Schroeder, and S. L. Bazin. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

Limit dextrinase was prepared from malted barley with a high degree of purity and a yield of 17% of the total limit dextrinase. Enzyme activity was not affected by dithiothreitol, indicating that limit dextrinase is not a sulfhydryl enzyme. However, enzyme levels were enhanced significantly in the presence of proteins such as bovine serum albumen (BSA); the pH optimum of the enzyme was also affected by BSA. The enzyme was inhibited strongly by low levels (100 micrograms/ml) of beta-cyclodextrin. Low levels of enzyme activity were present in barley, but enzyme levels increased rapidly during germination in a manner similar to that of alpha-amylase. A significant proportion of malt limit dextrinase was present in malt extracts in a soluble but inactive form. Conditions were established for the complete extraction of active limit dextrinase from malt and from barley germinated for varying periods of time (one to eight days).