Wong D W, Batt S B, Robertson G H
Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA.
J Agric Food Chem. 2000 Oct;48(10):4540-3. doi: 10.1021/jf000043z.
A microassay was developed for measuring the activity of alpha-amylases in the nanogram enzyme concentration range, based on the use of dye-labeled cross-linked starch as the substrate, and the release of soluble colored fragments formed in enzyme hydrolysis. Reaction conditions were optimized to generate a linear correlation between the increase in absorbance and a reaction time of 0-10 min, as well as enzyme concentrations in the range of 0-50 ng. A standard curve for the conversion of absorbance to enzyme activity units was constructed. The protocol developed was applied to monitoring the production of ultralow concentrations of recombinant barley alpha-amylase in yeast cells.
