L-Asparaginase from E. coli

Part I. Crystallization and Properties

Abstract

L-Asparaginase [EC 3.5.1.1], antitumor enzyme, was purified to a crystalline form from the cell free extract of Escherichia coli A-1-3 KY3598, by ethanol fractionation and chromato-graphies on DEAE cellulose and CM Sephadex. The crystalline enzyme was homogeneous by the criteria of ultracentrifugation: s₂₀, w was 7.87S.
The molecular weight was estimated to be 141, 000 by the short column method. The pI of the enzyme protein was 4.75 according to isoelectric electrofocusing.
Amino acid analysis revealed the absence of cysteine or cystine residues in the molecule.
The enzyme exhibited optimal activity between pH 6 and 8. It was stable in the pH range 5.5_??_9.0.
The enzyme activity was cleared very slowly in the plasma of dog. Intravenous administration of the enzyme caused a complete regression of the Gardner lymphoma implanted in the C3H mice.