One-step purification and kinetic properties of the recombinant L-asparaginase from Erwinia carotovora

ECAR-LANS, the recombinant L-asparaginase from Erwinia carotovora, is a prospective therapeutic enzyme for leukaemia treatment. An efficient and economical scheme was developed for the purification, cloning and expression in Eschericha coli of ECAR-LANS. More than 90% purity, complemented with 72% active enzyme recovery, was achieved with a single chromatographic purification step. The activity of purified L-asparaginase was 630 iu./mg. The ECAR-LANS K-m value was 98 x 10(-6) M for the main physiological substrate L-Asn and 3400 x 10(-6) M for L-Gln. ECAR-LANS was found to have low relative glutanninase activity (1.2%) at physiological concentrations Of L-Asn and L-Gln in blood. Kinetic studies of ECAR-LANS showed that the recombinant asparaginase combined the main advantages of Erw. chrysanthemi and E. coli L-asparaginases II, currently used in the treatment of acute lymphoblastic leukaemia.