Abstract

The α-amylases are required for the break of starch into oligosaccharides. Because starch has the most solubility at high temperatures, thermo stable α-amylase play a key role in industrial hydrolysis. The temperature effects on not only the enzyme structure, but also enzyme activity. The bacillus licheniformis itself is not a thermopile but it contains a rather thermo stable α-amylase that is the most widely used as α-amylase in the starch industry. In the present study, we made structure of nano tube-active site of this enzyme and focused mainly on the thermo stability. On the other hand, in this theoretical study, we studied the influence of the nano tube on the relative stability of enzyme and this information was compared with experimental data. At first, nano tube–active site of α-amylase was optimized then Quantum chemical calculations were performed by the GAUSSIAN 98 program. IR parameters consisting thermo chemical parameters were calculated on the optimized structure. Our results clearly indicated that in comparison with experimental investigations, nano tube play an important role in the enzyme's thermo stability, so that the most stable condition can be observed in the case of nano tube- enzyme.

Key words: Bacillus licheniformis α-amylase, nano tube, thermodynamic parameters,gaussian 98, ab initio, density functional theory.