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Date of Award
Bachelor of Arts (BA)
Department of Biology
Jonathan D. Monroe
Experimental evidence indicates that the family of beta-amylase (BAM) proteins is largely responsible for the hydrolysis of starch in land plants. In Arabidopsis thaliana there are nine BAM genes, six of which are targeted to the chloroplast, but only four of those are presumed to be catalytically active: BAM1, -2, -3, and -6. Currently, little is known about the expression, characterization, or function of BAM6. Our study of starch accumulation in Arabidopsis indicates that BAM6 may be playing a role in older plants, although it has a minimal role in young plants. To further investigate the function of BAM6 we over-expressed the BAM6 protein by ligating the mature protein coding sequence in fusion with a His-tag into pETDuet-1, an E. coli expression vector and purified the protein by affinity chromatography. Using the purified BAM6 protein, beta-amylase activity assays were conducted to begin to characterize BAM6. The effects of pH and temperature on BAM6 activity revealed maximum activity at pH 7.5 and 39 °C, which more closely resembles the profile of BAM1, an enzyme that is known to function primarily during the day. These findings indicate that BAM6 may also contribute to starch metabolism mostly during the day.
Torres, Catherine E., "The Purification and Characterization of Beta-amylase6 in Arabidopsis thaliana" (2016). Senior Honors Projects, 2010-current. 221.