Thermodynamic Properties of the β-glucosidase from Thermotoga maritima Extend the Upper Limit of Thermophilicity

Title:Thermodynamic Properties of the β-glucosidase from Thermotoga maritima Extend the Upper Limit of Thermophilicity

Volume: 21 Issue: 12

Author(s): Muhammad A. Mehmood, Izzah Shahid, Khadim Hussain, Farooq Latif and Muhammad I. Rajoka

Affiliation:

Keywords: β-glucosidase, heterologous expression, low-cost production, Thermotoga maritima, thermophilic.

Abstract: Enzymes from thermophilic organisms are believed to be strong candidates for industrial applications due to their ability to withstand temperature-induced enzyme inactivation. The present study demonstrated molecular cloning, over-expression, purification and characterization of β-glucosidase from Thermotoga maritima. The bglA gene with a capacity to encode a 51 kDa enzyme was heterologously expressed in E. coli M15. The enzyme was produced @130 mgL^-1 in LB media and @440 mgL^-1 in Dubos salt medium accounting 40-47 % of total cellular soluble proteins when lactose was used as an inducer. The enzyme showed a peak activity between pH and temperature range of 5.0-7.0 and 80-100 °C, respectively. The activity was fairly stable up to 140 °C. The turnover rate (k_cat) of the enzyme was 187.1±20 s^-1, whereas the K_m and V_max values were 0.56 mM and 238±2.4 IU mg^-1 protein, respectively. The enzyme was shown to have half-life of 136, 71 and 12.6 h at 80, 90 and 100 °C, respectively. Thermodynamics parameters including melting temperature (130 °C), activation energy for inactivation (36.92 kJmole^-1), enthalpy (33.73 kJmole^-1), Gibb’s free energy (127.96 kJmole^-1) and entropy (-246.46 Jmole^-1K^-1) have shown that the enzyme have enhanced hydrophobic interactions to prevent its thermal unfolding. These features endorse the industrial applications of the enzyme.

Cite this article as:

Mehmood A. Muhammad, Shahid Izzah, Hussain Khadim, Latif Farooq and Rajoka I. Muhammad, Thermodynamic Properties of the β-glucosidase from Thermotoga maritima Extend the Upper Limit of Thermophilicity, Protein & Peptide Letters 2014; 21 (12) . https://dx.doi.org/10.2174/0929866521666140616123104