title: L-Asparaginase from Erwinia Chrysanthemi 3937: cloning, expression and characterization.
abstract: Bacterial L-asparaginases (L-ASNases) catalyze the conversion of L-asparagine to L-aspartate and ammonia. In the present work, we report the cloning and expression of L-asparaginase from Erwinia chrysanthemi 3937 (ErL-ASNase) in Escherichia coli BL21(DE3)pLysS. The enzyme was purified to homogeneity in a single-step procedure involving cation exchange chromatography on an S-Sepharose FF column. The enzymatic and structural properties of the recombinant enzyme were investigated and the kinetic parameters (K(m), k(cat)) for a number of substrates were determined. In addition, we found that the enzyme can be efficiently immobilized on epoxy-activated Sepharose CL-6B. The immobilized enzyme retains most of its activity (60%) and shows high stability at 4 degrees C. The approach offers the possibility of designing an ErL-ASNase bioreactor that can be operated over a long period of time with high efficiency, which can be used in leukaemia therapy.
authors.affiliation: Laboratory of Enzyme Technology, Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
authors.forename: Georgia A
authors.initials: GA
authors.lastname: Kotzia
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Labrou
mesh_terms: D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism; D001215:Asparaginase / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D016974:Dickeya chrysanthemi / Q000201:enzymology*; D004926:Escherichia coli / Q000235:genetics; D006358:Hot Temperature; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013237:Stereoisomerism
chemical_list: D000970:Antineoplastic Agents; D001426:Bacterial Proteins; D001215:Asparaginase