| physical properties of l-asparaginase from serratia marcescens. | purified l-asparaginase from serratia marcescens had an apparent-weight average molecular weight of 171,000 to 180,000 as determined by electrophoresis on polyacrylamide gels and by sedimentation equilibrium at low speed in an analytical ultracentrifuge. a subunit molecular weight of 31,500 +/- 1,500 was estimated for the enzyme after treatment with sodium dodecyl sulfate and urea and electrophoresis on polyacrylamide gels; a similar value was obtained by high-speed sedimentation equilibrium in ... | 1976 | 1107330 |
| preliminary crystal structure of acinetobacter glutaminasificans glutaminase-asparaginase. | the preliminary structure of a glutaminase-asparaginase from acinetobacter glutaminasificans is reported. the structure was determined at 3.0-a resolution with a combination of phase information from multiple isomorphous replacement at 4-5-a resolution and phase improvement and extension by two density modification techniques. the electron density map was fitted by a polypeptide chain that was initially polyalanine. this was subsequently replaced by a polypeptide with an amino acid sequence in a ... | 1988 | 3275637 |
| characterization of crystals of l-glutaminase-asparaginase from acinetobacter glutaminasificans and pseudomonas 7a. | | 1977 | 875029 |
| studies of two crystal forms of l-glutaminase-asparaginase from acinetobacter glutaminasificans. | | 1975 | 1206706 |
| crystal structure and allosteric regulation of the cytoplasmic escherichia coli l-asparaginase i. | ansa is the cytoplasmic asparaginase from escherichia coli involved in intracellular asparagine utilization. analytical ultracentifugation and x-ray crystallography reveal that ansa forms a tetrameric structure as a dimer of two intimate dimers. kinetic analysis of the enzyme reveals that ansa is positively cooperative, displaying a sigmoidal substrate dependence curve with an [s](0.5) of 1 mm l-asparagine and a hill coefficient (n(h)) of 2.6. binding of l-asparagine to an allosteric site was ob ... | 2007 | 17451745 |
| expression, purification and crystallization of helicobacter pylori l-asparaginase. | the l-asparaginases from escherichia coli and erwinia chrysanthemi are effective drugs that have been used in the treatment of acute childhood lymphoblastic leukaemia for over 30 years. however, despite their therapeutic potential, they can cause serious side effects as a consequence of their intrinsic glutaminase activity, which leads to l-glutamine depletion in the blood. consequently, new asparaginases with low glutaminase activity, fewer side effects and high activity towards l-asparagine ar ... | 2008 | 18678946 |
| kinetic properties and inhibition of acinetobacter glutaminase-asparaginase. | kinetic parameters, substrate specificity and exclusivity of ligands at binding sites of l-glutaminase-l-asparaginase purified from acinetobacter glutaminasificans were studied in order to gain knowledge about the dual activities of this enzyme and its inhibition by structural analogs. both l-glutamine and l-asparagine, which showed similar km (4 approximately 7 x 10(-5) m) and vmax (molecular activity 1.0 min-1) values, were competitive with each other for the substrate binding site. the produc ... | 1983 | 6838661 |
| structures of amidohydrolases. amino acid sequence of a glutaminase-asparaginase from acinetobacter glutaminasificans and preliminary crystallographic data for an asparaginase from erwinia chrysanthemi. | the complete amino acid sequence of a glutaminase-asparaginase from acinetobacter glutaminasificans, for which a preliminary tertiary structure is available from crystallographic analysis, has been determined by automated edman degradation of fragments produced by chemical and proteolytic cleavages. the protein consists of 331 amino acid residues and has a molecular weight of 35,500. the pattern of hydrophilic and hydrophobic regions is typical of a globular protein. a new crystal form of an erw ... | 1988 | 3379033 |
| refined crystal structure of acinetobacter glutaminasificans glutaminase-asparaginase. | the crystal structure of glutaminase-asparaginase from acinetobacter glutaminasificans has been reinterpreted and refined to an r factor of 0.171 at 2.9 a resolution, using the same x-ray diffraction data that were used to build a preliminary model of this enzyme [ammon, weber, wlodawer, harrison, gilliland, murphy, sjölin & roberts (1988). j. biol. chem. 263, 150-156]. the current model, which does not include solvent, is based in part on the related structure of escherichia coli asparaginase a ... | 1994 | 15299349 |
| the glutaminase activity of l-asparaginase is not required for anticancer activity against asns-negative cells. | l-asparaginase (l-asp) is a key component of therapy for acute lymphoblastic leukemia. its mechanism of action, however, is still poorly understood, in part because of its dual asparaginase and glutaminase activities. here, we show that l-asp's glutaminase activity is not always required for the enzyme's anticancer effect. we first used molecular dynamics simulations of the clinically standard escherichia coli l-asp to predict what mutated forms could be engineered to retain activity against asp ... | 2014 | 24659632 |
| structural insight into substrate selectivity of erwinia chrysanthemi l-asparaginase. | l-asparaginases of bacterial origin are a mainstay of acute lymphoblastic leukemia treatment. the mechanism of action of these enzyme drugs is associated with their capacity to deplete the amino acid l-asparagine from the blood. however, clinical use of bacterial l-asparaginases is complicated by their dual l-asparaginase and l-glutaminase activities. the latter, even though representing only ∼10% of the overall activity, is partially responsible for the observed toxic side effects. hence, l-asp ... | 2016 | 26855287 |
| sorting the chaff from the wheat at the pdb. | | 2008 | 19177345 |
| sorting the chaff from the wheat at the pdb. | | 2008 | 19177345 |
| current applications and different approaches for microbial l-asparaginase production. | l-asparaginase (ec 3.5.1.1) is an enzyme that catalysis mainly the asparagine hydrolysis in l-aspartic acid and ammonium. this enzyme is presented in different organisms, such as microorganisms, vegetal, and some animals, including certain rodent's serum, but not unveiled in humans. it can be used as important chemotherapeutic agent for the treatment of a variety of lymphoproliferative disorders and lymphomas (particularly acute lymphoblastic leukemia (all) and hodgkin's lymphoma), and has been ... | 2016 | 27866936 |