Studies on pH and thermal stability of novel purified L-asparaginase from Pectobacterium carotojorum MTCC 1428.

Glutaminase free L-asparaginase is known to be an excellent anticancer agent. In the present study, the combined effect of pH and temperature on the performance of purified novel L-asparaginase from Pectobacterium carotovorum MTCC 1428 was studied under assay conditions using response surface methodology (RSM). Deactivation studies and thermodynamic parameters of this therapeutically important enzyme were also investigated. The optimum pH and temperature of the purified L-asparaginase were found to be 8.49 and 39.3 degrees C, respectively. The minimum deactivation rate constant (k(d)) and maximum half life (t1/2) were found to be 0.041 min(-1) and 16.9 h, respectively at pH of 8.6 and 40 degreesC. Thermodynamic parameters (deltaG, deltaH, deltaS, and activation energies) were also evaluated for purified L-asparaginase. The probable mechanism of deactivation of purified L-asparaginase was explained to an extent on the basis of deactivation studies and thermodynamic parameters.