Purification and Characterization of L-asparaginase from Erwinia carotovora

摘要

An L-asparaginase from Erwinia carotovora was successively purified by ammonium sulfate precipitation, DEAE-cellulose and Sephacryl S-200 columns. The specific activity of the L-asparaginase was increased approximately 55-fold, from 15.5 to 852 U/mg proteins. SDS-PAGE showed that the purified L-asparaginase was homogeneous and the molecular weight was about 115 kDa. The isoelectric point (pI) of the enzyme was about 5.9. Characterization of the enzyme exhibited optimum pH and temperature of 8.4 and 40℃, respectively. The purified enzyme is able to prolong its thermal stability up to 50℃. A Lineweaver-Burk analysis showed a K_m value of 0.154 mM and V_(max) of 41.67 U. The purified enzyme was rich in glycine, alanine, glutamic acid and aspartic acid.