Isolation and Characterization of Glutaminase-free L-asparaginase Produced by Staphylococcus sp. MGM1

L-asparaginase is an important therapeutic enzyme used in combination with other drugs for therapy of Acute Lymphoblastic Leukemia (ALL). L-asparaginase catalyzes the conversion of asparagine to aspartic acid and ammonia. In recent years, this enzyme gained applications in many fields of science such as clinical research, pharmacological, and food industries. This study was aimed at isolation and identification of a strain with the ability to producing extracellular glutaminase free L-asparaginase from soil and determination of enzyme stability. The isolation was done on M9 medium. Biochemical tests and 16S rDNA sequence was used for strain identification. L-asparaginase was partially purified using ammonium sulfate precipitation, dialysis, and DEAE-anion exchange chromatography. The effect of pH and temperature on enzyme activity was investigated. The isolated bacteria were identified as Staphylococcus sp. The optimum pH and temperature for maximum L-asparaginase activity were found at 8 and 35 °C. The enzyme purification showed a single band around 115 kDa on SDS-Page. The optimal activity for the enzyme produced by MGM1 was similar to the physiological conditions of the human body, therefore, further studies on this enzyme would be of great value in finding a new efficient asparaginase enzyme.