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)

Tyrosine phenol-lyase from Erwinia herbicola was purified with the goal of assessing its effect on growth of malignant melanoma. Ammonium sulfate-sodium citrate fractionation and diethylaminoethyl cellulose-hydroxylapatite chromatography were used. The purified enzyme was shown to reduce plasma tyrosine levels when administered to normal C57BL x DBA/2 F1 mice. The plasma half-life value of the enzyme was found to be 6 to 7 hr. Unlike results reported with glutaminase and asparaginase preparations, the lactate dehydrogenase-elevating virus had no significant influence on plasma clearance of tyrosine phenol-lyase. The enzyme significantly inhibited growth of established B-16 melanoma tumors.
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PMID:Some biological properties and an in vivo evaluation of tyrosine phenol-lyase on growth of B-16 melanoma. 124 96

The ph optimum of purified staphylococcal L-asparaginase (EC 3.5.1.1) was found to be between 8.6 and 8.8. The temperature optimum was 30 degrees-32 degrees C and the highest reaction rate occurred at 30 degrees C. The KM of the enzyme calculated from Lineweaver-Burk plot was 3.71 x 10(-2) M. Besides L-asparaginase, the substrate specificity of enzyme was restricted to N-alpha-acetyl-L-asparagine. D-asparagine, L-aspartic acid and D-glutamic acid were competitive inhibitors. Hg2+ and Cu2+ cations strongly inhibited the enzyme while Na+ and K+ cations strongly stimulated activity. Two SH-groups could be detected after enzyme denaturation with guanidine.
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PMID:Staphylococcal L-asparaginase: enzyme kinetics. 172 15

Studies on L-asparaginase synthesis in V. proteus showed increased synthesis in cultures grown under conditions of moderate aeration (P less than 0.005) after oxygen had been used up from the medium. Addition of sodium lactate to the medium at a concentration of 80 mu mole/ml, stimulated L-asparaginase synthesis (2.2 times over control) in moderately-aerated cultures (P less than 0.001). The substrate L-asparagine induced enzyme synthesis when growth conditions were made anaerobic or lactate was incorporated into the medium (3.8 times increased enzyme synthesis over control).
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PMID:Induction of L-asparaginase synthesis in Vibrio proteus. 177 15

L-Asparaginase of T. pyriformis is a membrane-bound enzyme with an active site situated on the outside surface of the membrane. When radioactive L-asparagine was incubated with T. pyriformis cells in the L-asparaginase assay medium, the hydrolysis was 240 higher than the uptake of this amino acid. In a similar experiment performed in salt medium (Wagner's solution), the hydrolysis was linearly increased and reached after one hour of incubation a value of 60 nmol/10(6) cells, while the uptake after 20 min of incubation reached a plateau with a value of 15 nmol/10(6) cells. The uptake of L-leucine under these conditions was 44 nmol/10(6) cells/hr, while no measurable transport of aspartic acid was observed. That L-aspartic acid is not migrated into T. pyriformis cells is in agreement with the finding that no efflux of this amino acid takes place as well. The uptake of L-asparagine is pH and K+ dependent, whereas Na+ ions strongly inhibit this uptake. The Km and Vmax values of L-asparagine uptake is 1.43 mM and 0.7 nmol/min, respectively. The half life of L-asparagine "protein transport system" was 40 min, a value which is very close to the half life of the membrane-bound L-asparaginase of this microorganism. Ouabain and vanadate inhibit the uptake of L-asparagine by more than 80%, while ouabain or vanadate inhibit in vivo 5% or 95% the activity of L-asparaginase, respectively. This indicates the lack of interrelationship between the L-asparagine "protein transport system" and the L-asparaginase protein molecule.
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PMID:Transport of L-asparagine in Tetrahymena pyriformis ecto-L-asparaginase is not related to L-asparagine-protein transport system. 193 Feb 47

We performed analyses of electrolytes, amino acids, albumin, alpha 2-macroglobulin, gamma-globulin and LDH in the lumbar cerebrospinal fluid of children undergoing treatment for acute lymphoblastic leukemia, non-Hodgkin-lymphoma or acute myeloid leukemia. At the time of diagnosis signs of a disturbance of the blood-brain barrier were found in some patients. During induction treatment with L-asparaginase a rise of glutamic acid and a decrease of glutamine occurred. This finding correlated with slowing of the EEG. Treatment with vincristine was associated with a slight drop of sodium and chloride concentration in serum, but not in the cerebrospinal fluid. Central nervous system prophylaxis with cranial irradiation, and to a lesser degree with intravenous medium-dose methotrexate, gave rise to a further deterioration of the blood-brain barrier function as indicated by an increase in albumin, alpha 2-macroglobulin and LDH levels. During radiotherapy the concentration of several amino acids rose, probably due to a disturbance of active carrier mechanisms. Patients with elevated albumin at the end of radiotherapy more often suffered an early leukemia relapse while still on treatment. No other clinical or electroencephalographic correlations of altered barrier function could be found.
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PMID:Electrolytes, amino acids and proteins in lumbar CSF during the treatment of acute leukemia in childhood. 233 48

A large-scale process was developed to purify L-asparaginase from submerged cultures of Erwinia carotovora. Cells from 880 L of fermentation broth were harvested and washed using a plate and frame type filter press. A cellular acetone powder was prepared from the washed cells by suspending the cells twice in acetone and the residual acetone was removed by washing the acetone powder in the filter press with 10 mM phosphate buffer (pH 7.0). The cellular acetone powder was extracted with 10 mM borate buffer at pH 9.5. The enzyme-rich borate extract was recovered by filtration and clarified by an in-line bag filter. The filtrate was adjusted to pH 7.5 and filtered through a 1-micron bag filter precoated with Celite and then through a 0.22-micron cartridge filter. The cell-free extract, containing 21 x 10(6) IU of enzyme and 448 g of total protein, was applied to an L-asparagine Sepharose 6 Fast Flow affinity column (9 L) using a bag filter loaded with Cell Debris Remover as an in-line prefilter. The affinity gel was prepared by coupling L-Asn at pH 9.0 to epoxy-activated Sepharose 6 Fast Flow beads. A total of 14 x 10(6) IU of enzyme (35 g protein) was eluted at pH 9.0 in 10.5 L. The eluted enzyme was determined to be greater than 90% pure using sodium dodecyl sulfate polyacrylamide gel electrophoresis. The total process time from whole broth to affinity column elution was 68 h and the enzyme yield was 38%. This improved process for the 880 L fermentation broth produced a cell-free extract of high specific activity, shortened the process time, increased the column capacity, and yielded a product with high purity.
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PMID:L-asparaginase from Erwinia carotovora. An improved recovery and purification process using affinity chromatography. 280 97

Purified preparations of asparaginase II of Saccharomyces cerevisiae exhibit two protein bands upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cloning and sequencing of the ASP3 gene, and partial amino acid sequencing as asparaginase II, imply that both bands are encoded by ASP3 but have different N termini. Northern blot analysis using the cloned ASP3 gene as a probe indicates that nitrogen catabolite repression of asparaginase II is achieved by alteration in mRNA levels. Deletion of sequences greater than 600 base pairs upstream from the initiation AUG codon results in an altered response to certain nitrogen sources in strains containing the truncated gene.
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PMID:Asparaginase II of Saccharomyces cerevisiae. Characterization of the ASP3 gene. 304 86

To determine if factor VIII-von Willebrand factor (vWF) complex is involved in the thrombosis associated with asparaginase-prednisone-vincristine induction therapy for acute lymphoblastic leukemia, plasma vWF was analyzed by sodium dodecyl sulfate-agarose gel electrophoresis and crossed immunoelectrophoresis. Five patients with cerebral thrombosis were studied; all had a decreased platelet count following the complication. Sequential studies of three patients disclosed changes in plasma vWF multimer pattern. One patient who was studied serially from 2 days before to 1 day after the event, had an increase in unusually large plasma vWF multimers that disappeared after the complication. The other two patients who were studied at presentation subsequently showed a decrease in plasma large vWF multimers, especially remarkable in the patient having the sharpest decrease in platelet count. No appreciable difference in vWF multimer pattern, when compared to normal pooled plasma, was found in the remaining two patients who were only studied at presentation, or in the seven controls who received the same treatment but did not develop thrombosis. Crossed immunoelectrophoretic analyses of two patients tested disclosed a right shift of immunoprecipitin line in one and a left shift in the other. Our findings suggest that the thrombotic complications resulted from platelet agglutination by plasma vWF.
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PMID:Involvement of von Willebrand factor in thrombosis following asparaginase-prednisone-vincristine therapy for leukemia. 311 Dec 51

L-Asparaginase activity reaches maximal values at the stationary phase of growth of Tetrahymena pyriformis and fluctuates upon the growth conditions and the composition of the medium. Most of the L-asparaginase activity (80%) is associated with the endoplasmic reticulum, and the remaining with the pellicles. Detergents either alone or in combination with NaCl up to 0.5 M concentration failed to solubilize L-asparaginase. Solubilization can be accomplished by means of either the chaotropic agents KSCN and NaClO4, or 0.1 M sodium phosphate buffer pH 8.0, following pretreatment of the particulates with 2% w/v Triton X100. L-Asparaginase has been purified to near homogeneity by hydrophobic and gel filtration chromatography. The native enzyme has a relative molecular weight of 230,000. It is a multiple subunit enzyme, with subunit size of 39,000. Its isoelectric point is at pH 6.8. It acts optimally at pH 8.6 with a Km of 2.2 mM. It does not hydrolyse L-glutamine and its reaction is inhibited competitively by D-aspartic acid and D-asparagine as well as by L-asparagine analogues with substituents at the beta position.
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PMID:Purification and properties of a membrane-bound L-asparaginase of Tetrahymena pyriformis. 313 90

A technique for purification of glutamine asparaginase from Pseudomonas boreopolis 526 is described which provides a 37% yield of the enzyme homogeneous according to electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate. The effect of pH, freezing, thawing and lyophilic drying on the stability of glutamine asparaginase was studied. The enzyme is rather stable at pH 4.8 and 4 degrees C. Lyophilic drying of the homogeneous enzyme without addition of stabilizers resulted in a decrease of its activity an is accompanied by formation of protein conglomerates with molecular weights of 280,000 and 660,000 D. Freezing and thawing decreased the activity of the nature enzyme by 40-50%.
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PMID:[Isolation, purification and stability of a glutamin(asparagin)ase preparation from Pseudomonas boreopolis 526]. 344 13


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