PURIFICATION AND PROPERTIES OF ASPARAGINASE FROM ESCHERICHIA COLI B

Escherichia coli B asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) has been purified ca. 2000-fold by a combination of heat denaturation, gel filtration, chromatography on DEAE-cellulose, and calcium hydroxylapatite, and polyacrylamide gel electrophoresis. The enzyme appears to be homogeneous, as judged by several criteria, including sedimentation equilibrium ultracentrifugation, disc electrophoresis, and immunoelectrophoresis. At 0.1% protein concentration, the molecular weight by equilibrium sedimentation was found to be ca. 139,000. In 8 M urea or 5 M guanidinium hydrochloride, dissociation to an inactive species with an apparent molecular weight of 19,000-24,000 was observed. The amino acid composition has been determined, as well as certain other properties of the enzyme. © 1969, American Chemical Society. All rights reserved.