Advances in Research of Mechanisms of Thermostability of Thermozymes

Thermophiles and hyperthermophiles screened from extreme environments are the main source of thermozymes. Because of thermophiles' harsh cultural condition and low enzyme quantities, gene engineering and protein engineering are also methods of obtaining thermozymes. At the present time, It is a major method of research on the thermostability of thermozymes to compare the homology of amino acid sequence between thermozymes and mesophilic enzymes. The different enzymes have different mechanisms of thermostability. The amino acid composition between thermozymes and their mesophilic counterparts is different in the primary structure. α-helix stabilization increases thermozymes' stability in secondary structure. In advanced structure, internal factors of thermophilic enzymes are of importance, such as additional ionic networks, hydrophobic interactions, hydrogen bonds, cooperative association, etc. Some environmental factors have effect on thermostability of thermozymes.