Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.1 (asparaginase)
2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

L-Asparaginase, a major component of therapy in children with acute lymphoblastic leukemia, has been shown to induce coagulopathy by inhibiting synthesis of clot-forming and clot-inhibitory proteins. The authors report the successful use of recombinant factor VIIa in a 15-year-old girl with acute lymphoblastic leukemia who had L-asparaginase-induced intracranial hemorrhage. The present case is the first to demonstrate use of rFVIIa in L-asparaginase-induced intracranial hemorrhage in a child with acute lymphoblastic leukemia.
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PMID:Successful treatment of acute lymphoblastic leukemia with L-asparaginase-induced intracranial hemorrhage to activated recombinant factor VIIa in a child. 1662 76

L-Asparaginase is commonly used in combination chemotherapy of both pediatric and adult acute lymphoblastic leukemia. The majority of adverse effects are hypersensitivity reactions, but serious liver injury may also occur. It has been shown that treatment with L-asparaginase can be associated mainly with macrovesicular hepatic steatosis which may be accompanied by alterations in lipid metabolism. So far, the mechanism for liver injury associated with L-asparaginase is not known. We report here an adult patient who developed mixed liver injury and predominantly microvesicular hepatic steatosis while being treated with L-asparaginase for acute lymphoblastic leukemia. The patient developed liver failure and died due to multiorgan failure. Both impaired liver mitochondrial function and alterations in very-low-density lipoprotein metabolism and secretion are discussed as two possible mechanisms explaining the findings observed in this patient.
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PMID:Fatal liver failure in an adult patient with acute lymphoblastic leukemia following treatment with L-asparaginase. 1698 8

L-Asparaginase is an effective antineoplastic agent, used in the acute lymphoblastic leukemia chemotherapy. It has been an integral part of combination chemotherapy protocols of pediatric acute lymphoblastic leukemia for almost 3 decades. The potential of L-asparaginase as a drug of leukemia has been a matter of discussion due to the high rate of allergic reactions exhibited by the patients receiving the medication of this enzyme drug. Frequent need of intramuscular injection has been another disadvantage associated with the native preparation. However, of late these clinical complications seem to have been addressed by modified versions of L-asparaginase. PEG-L-asparaginase proves to be most effective in this regard. It becomes important to discuss the efficacy of L-asparaginase as an antileukemic drug vis-a-vis these disadvantages. In this review, an attempt has been made to critically evaluate the pharmacological and clinical potential of various preparations of L-asparaginase as a drug. Advantages of PEG-L-asparaginase over native preparations and historical developments of therapy with l-asparaginase have also been outlined in the review below.
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PMID:Pharmacological and clinical evaluation of L-asparaginase in the treatment of leukemia. 1701 87

L-Asparaginase shows antileukemic activity and is generally administered in the body in combination with other anticancer drugs like pyrimidine derivatives. In the present study, L-asparaginase was purified from a bacteria Erwinia carotovora and the effect of a dihydropyrimidine derivative (1-amino-6-methyl-4-phenyl-2-thioxo, 1,2,3,4-tetrahydropyrimidine-5-carboxylic acid methyl ester) was studied on the kinetic parameters Km and Vmax of the enzyme using L-asparagine as substrate. The enzyme had optimum activity at pH 8.6 and temperature 35 degrees C, both in the absence and presence of pyrimidine derivative and substrate saturation concentration at 6 mg/ml. For the enzymatic reaction in the absence and presence (1 to 3 mg/ml) of dihydropyrimidine derivative, Km values were 7.14, 5.26, 4.0, and 5.22 M, and Vmax values were 0.05, 0.035, 0.027 and 0.021 mg/ml/min, respectively. The kinetic values suggested that activity of enzyme was enhanced in the presence of dihydropyrimidine derivative.
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PMID:Purification of L-asparaginase from a bacteria Erwinia carotovora and effect of a dihydropyrimidine derivative on some of its kinetic parameters. 1728 5

A novel fusion protein designed to facilitate protein purification was expressed in Escherichia coli and purified separately by two different chromatography methods. L-Asparaginase from Erwinia chrysanthemi is fused to the N-terminus of a model peptide, alpha-human atrial natriuretic peptide (alpha-hANP). L-Asparaginase was chosen because of its selective affinity for L-asparagine and because of its unusually high isoelectric point(8.6). A gene construction without the L-asparaginase native signal sequence caused expression at a level of 8% of total cell protein, while gene construction with the native signal sequence resulted in over five time less expression. The hybrid protein expressed without the signal sequence was purified from clarified cell lysate byeither L-asparagine affinity chromatography or cation exchange chromatography. After digestion of the fusion protein with factor Xa protease, a peptide with a molecular weight corresponding to the theoretical molecular weight of alpha-hANP was observed by coupled HPLC/mass spectrometry. (c) 1995 John Wiley & Sons Inc.
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PMID:Purification of an L-asparaginase-atrial natriuretic peptide fusion protein expressed in Escherichia coli. 1862 25

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 are highly desirable as better alternatives in cancer therapy. L-Asparaginase from Helicobacter pylori was overexpressed in E. coli and purified for structural studies. The enzyme was crystallized at pH 7.0 in the presence of 16-19%(w/v) PEG 4000 and 0.1 M magnesium formate. Data were collected to 1.6 A resolution at 100 K from a single crystal at a synchrotron-radiation source. The crystals belong to space group I222, with unit-cell parameters a = 63.6, b = 94.9, c = 100.2 A and one molecule of L-asparaginase in the asymmetric unit. Elucidation of the crystal structure will provide insight into the active site of the enzyme and a better understanding of the structure-activity relationship in L-asparaginases.
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PMID:Expression, purification and crystallization of Helicobacter pylori L-asparaginase. 1867 46

There is no standard salvage regimen for patients with refractory and relapsed extranodal NK/T-cell lymphoma (NKTCL), nasal type. This study was conduced to evaluate the efficacy of L-asparaginase-based regimen as a salvage regimen, on refractory and relapsed extranodal NKTCL, nasal type. Between March 1996 and March 2008, 45 patients with refractory and relapsed extranodal NKTCL, nasal type, were studied retrospectively. All patients were treated with L-asparaginase-based salvage regimen. Thirty-nine patients also received primary involved-field radiation after L-asparaginase-based chemotherapy. The complete response rate, partial response rate, and overall response rate for the whole group were 55.6%, 26.7%, and 82.2%, respectively. Both of 3-year and 5-year overall survival (OS) rates were 66.9%. The major adverse effects of L-asparaginase were myelosuppression, liver dysfunction, hyperglycemia, and allergic reaction. In general, the side effects could be tolerated. On univariate analysis, age, the stage of disease, and performance status were found to be prognostic factors influencing OS. On multivariate analysis, the stage of disease and age were independent prognostic factors for OS. L-Asparaginase-based regimen was obviously effective for the patients with refractory and relapsed extranodal NKTCL, nasal type.
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PMID:L-asparaginase in the treatment of refractory and relapsed extranodal NK/T-cell lymphoma, nasal type. 1910 82

Withania somnifera L. has been traditionally used as a sedative and hypnotic. The present study was carried out for the purification, characterization, and in vitro cytotoxicity of L-asparaginase from W. somnifera L. L-Asparaginase was purified from the fruits of W. somnifera L. up to 95% through chromatography. The purified L-asparaginase was characterized by size exclusion chromatography, polyacrylamide gel electrophoresis (PAGE), and 2D PAGE. The antitumor and growth inhibition effect of the L-asparaginase was assessed using [3-(4, 5-dimethyl-thiazol-2yl)-2, 5-diphenyl-tetrazolium bromide] (MTT) colorimetric dye reduction method. The purified enzyme is a homodimer, with a molecular mass of 72 +/- 0.5 kDa, and the pI value of the enzyme was around 5.1. This is the first report of the plant containing L-asparaginase with antitumor activity. Data obtained from the MTT assay showed a LD(50) value of 1.45 +/- 0.05 IU/ml. W. somnifera L. proved to be an effective and a novel source of L: -asparaginase. Furthermore, it shows a lot of similarity with bacterial L-asparaginases EC-2.
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PMID:Anticancer properties of highly purified L-asparaginase from Withania somnifera L. against acute lymphoblastic leukemia. 1944 78

The incidence of pancreatitis in patients with haematopoetic neoplasms who are treated with L-asparaginase is fom 2 to 24%. In majority of cases the pancreatitis is oedematous and self-limiting. Acute haemorrhagic or necrotizing pancreatitis caused by L-asparaginase is rare but potentially life-threatening complication. We present 2 cases of acute pancreatitis in children aged 2 and 4 years. They were diagnosed to have acute lymphoblastic leukaemia and were treated according to the ALLLIC BFM 2002 protocol. Acute pancreatitis developed in these children after induction therapy and was followed by formation of a pseudocyst. In both cases the diagnosis of this complication was made directly after phase I of the protocol I (after eighth dose of L-Asparaginase). In the first case the course of acute pancreatitis was mild. Normalization of the amylase levels occurred after 7 days and the diagnosis of post inflammatory cyst was made 15 days after the first signs of the disease. But thereafter, during the additional complication (pneumonia with Pseudomonas aeruginosa bacteriemia) the pancreatic cyst became infected. In the second case acute pancreatitis had a severe course and the child required treatment in the Intensive Care Unit for 21 days. The cyst was diagnosed after 20 days from the beginning of symptoms. The surgical procedure, applied in both cases was internal drainage by anastomosis of the cyst with the back wall of the stomach. Antileukaemic treatment was recommenced after 6-8 weeks when complications resolved. Currently both children are well and remain in haematological remission and continue maintenance chemotherapy.
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PMID:[Acute pancreatitis during chemotherapy of acute lymphoblastic leukaemia complicated with pseudocyst]. 1953 25

L-Asparaginase is an important component in the treatment of acute lymphoblastic leukemia in children. Its antineoplastic activity toward malignant cells is due to their characteristic nature in slow synthesis of L-asparagine (Asn), which causes starvation for this amino acid, while normal cells are protected from Asn starvation due to their ability to produce this amino acid. The relative selectivity with regard to the metabolism of malignant cells forces to look for novel asparaginase with little glutaminase-producing systems compared to existing enzyme. In this investigation, the role of the extracellular asparaginase enzyme produced by an isolated bacterial strain was studied. Biochemical characterization denoted that this isolated bacterial strain belongs to the Bacillus circulans species. The strain was tested for L-asparaginase production, and it was observed that, under an optimized environment, this isolate produces a maximum of 85 IU ml(-1) within 24-h incubation. This enzyme showed less (60%) glutaminase activity compared to commercial Erwinia sp. L-asparaginase. The partially purified enzyme showed an approximate molecular weight of 140 kDa. This enzyme potency in terms of antineoplastic activity was analyzed against the cancer cells, CCRF-CEM. Flow cytometry experiments indicated an increase of sub-G1 cell population when the cells were treated with L-asparaginase.
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PMID:Evaluation of antineoplastic activity of extracellular asparaginase produced by isolated Bacillus circulans. 1954 38


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