A highly stable manganese catalase from Geobacillus thermopakistaniensis: molecular cloning and characterization

Catalases, heme or manganese, are efficient biocatalysts that split hydrogen peroxide into water and oxygen. We have cloned a manganese catalase from thermophilic bacterium, Geobacillus thermopakistaniensis , and expressed the corresponding gene in Escherichia coli . The gene product, Cat Gt , was synthesized in E. coli as inactive inclusion bodies. Solubilization and refolding of the inclusion bodies resulted in highly active Cat Gt with a specific activity of 18,521 μmol min −1 mg −1 . The refolded protein exhibited apparent K m and k cat values of 260 mM and 10,360 s −1 subunit −1 , respectively. It exhibited a half-life of 1 h at 100 °C. The unique features of Cat Gt are its high activity and thermostability. These features make it a valuable catalyst for industrial applications. To the best of our knowledge, Cat Gt is the most thermostable catalases characterized to date.