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 i.u./mg. The ECAR‐LANS K m value was 98×10 −6 M for the main physiological substrate l ‐Asn and 3400×10 −6 M for l ‐Gln. ECAR‐LANS was found to have low relative glutaminase 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.