Purification and Characterization of an α-Amylase of Pichia burtonii Isolated from the Traditional Starter "Murcha" in Nepal
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Among more than 20 yeast strains isolated from the traditional starter "murcha" in Nepal, we characterized a yeast that might be involved in saccharification. This strain, identified as <I>Pichia burtonii</I>, produced an extracellular amylolytic enzyme when cultured in the presence of starch in the medium. Since no amylase secreted by <I>P. burtonii</I> has yet been reported, we purified the enzyme and determined its N-terminal amino acid sequence. Together with the results of a hydrolyzing activity assay toward various substrates, it was found to be an α-amylase. The purified enzyme, named <I>Pichia burtonii</I> α-amylase (PBA), was a glycoprotein with an apparent molecular mass of 51 kDa. Enzyme activity was optimal at pH 5.0 at 40 °C. The enzyme retained 80% of its original activity after incubation under the optimal pH condition at 50 °C for 30 min. The activity was inhibited by metal ions such as Cd<SUP>2+</SUP>, Cu<SUP>2+</SUP>, Hg<SUP>2+</SUP>, Al<SUP>3+</SUP>, and Zn<SUP>2+</SUP>.
- Agricultural and Biological Chemistry
Agricultural and Biological Chemistry 70(12), 3019-3024, 2006-12-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry