Influence of different metals on the activation and inhibition of ?-amylase from thermophilic Bacillus firmus KIBGE-IB28

Thermophilic Bacillus firmus KIBGE-IB28 produced extracellular ?-amylase at temperature 70°C. Enzyme was partially purified by ammonium sulfate precipitation with 42.80 fold purification and specific activity of 1889.6 U/mg. Effects of various metals on enzyme activity were determined and it was found that enzyme activity boosted significantly in presence of Ca2+, K2+, Ba2+, Co2+ and Ni2+ whereas Zn2+, Mg2+, Na2+ and Cu2+ were found inhibitory at concentration 10mM.