LIMIT DEXTRINASE FROM MALTED BARLEY - EXTRACTION, PURIFICATION, AND CHARACTERIZATION

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