• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1426-1431
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• 1998

The research was undertaken to characterize enzymatic properties of Streptomyces albus amylase expressed in recombinant Bacillus subtilis. Molecular weight and pI of the purified enzyme were estimated to be 50 kD by SDS-PAGE and 4.3 by isoelectric focusing. The optimum temperature and optimum pH were $45^{\circ}C$ and 6.0, respectively. D-and Z-value were estimated to measure thermostability of the purified enzyme. The Z-value was estimated $17.7^{\circ}C$, which is lower than typical amylase. Maltotetraose was produced as a major component from soluble starch in the early state of reaction but gradually degraded to maltose. Thin layer chromatography was also performed to analyze the reaction products. The parameters involved in Michaelis-Menten enzyme kinetics were found to be the maximum velocity of 0.37 mM/min and the Michaelis constant of 0.13%, respectively.