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)

Obvious protection of the catalytic activity of Esch. coli L-asparaginase by alpha 2-macroglobulin (alpha 2M) was observed under conditions otherwise propitious to the dissociation of the tetrameric molecule into inactive subunits, i.e. very diluted enzyme solutions or the presence of either SDS or urea. The degree of protection depended on enzyme and alpha 2M concentrations respectively, and on the preincubation time of the alpha 2M-enzyme mixture prior to substrate addition. The formation of a catalytically active complex between alpha 2M and L-asparaginase was confirmed by gel filtration on a Sephadex-G column and by polyacrylamide gel electrophoresis. The fact that the migration distance of the active complex corresponded to the migration of alpha 2M and the absence in that case of a migration band corresponding to the intact molecule suggest that complexing of the enzyme with alpha 2M prevented its dissociation into subunits and thus its inactivation. Addition of alpha 2M to the already dissociated enzyme molecule did not restore its catalytic activity. Alpha2-macroglobulin was shown to have an inhibiting effect on the proteolytic activity of almost all proteases and no effect on their esterolytic activity. Furthermore, it prevents the inhibition of esterolytic activity by some natural compounds. The effect of alpha 2M on other types of catalytic activity has not been investigated enough to afford a generalization of the possible role of this macroglobulin in the control of enzyme activity in the body. This paper reports the results of an in vitro study of the effect of alpha 2M on the catalytic activity of an important amidase, i.e. L-asparaginase (L-asparagine amidohydrolase 3.5.1.1), which in recent years has been used in the treatment of acute lymphocytic leukemia in children.
Mol Cell Biochem 1979 Feb 09
PMID:Interaction of alpha 2-macroglobulin with L-asparaginase. 9 Mar 34

An L-asparaginase cDNA clone, BR4, was isolated from a Lupinus arboreus Sims developing seed expression library by screening with polyclonal antibodies to the seed asparaginase. The cDNA hybridised with an oligonucleotide probe designed from amino acid sequence data and was found on sequencing to be 947 bp in length. Six polypeptide sequences obtained previously could be placed along the longest open reading frame. Computer-aided codon use analysis revealed that the cDNA sequence was consistent with other plant genes in terms of codon use. The cDNA insert was used to analyse asparaginase transcription in various tissues by northern blot analysis. A transcript size of approximately 1.2 kb was detected in L. arboreus seed total and poly(A)+ RNA. The level of this transcript declined from 30 days after anthesis to an undetectable level by day 55. Furthermore, under the high stringency conditions used, the seed asparaginase cDNA did not hybridise with total or poly(A)+ RNA isolated from root tips, suggesting that the asparaginase known to be present in this tissue may be the product of a different gene. Southern analysis suggested the seed asparaginase is a single-copy gene. The plant asparaginase amino acid sequence did not have any significant homology with microbial asparaginases but was 23% identical and 66% similar (allowing for conservative substitutions) to a human glycosylasparaginase.
Plant Mol Biol 1992 Jun
PMID:The isolation and characterisation of a cDNA clone encoding L-asparaginase from developing seeds of lupin (Lupinus arboreus). 137 63

A genomic sequence encoding Lupinus angustifolius L-asparaginase has been obtained, and is the first report of this gene from a plant source. The 3.2 kb of DNA sequenced contains a 1136 bp 5' flanking sequence, four exons and three introns. Intron-exon borders were mapped by comparing the genomic sequence with that of a L. arboreus cDNA. Primer extension analysis revealed transcription start sites 16 bp and 13 bp 5' of the initiating ATG for L. angustifolius and L. arboreus, respectively. The 5' flanking region contained sequences associated with seed-specific expression.
Plant Mol Biol 1992 Oct
PMID:Molecular cloning of the gene encoding developing seed L-asparaginase from Lupinus angustifolius. 139 78

The plasmid RP4::Mu cts62 in stably inherited by Erwinia carotovora 268 strain. Under the conditions of thermoinduction bacteriophage Mu is segregated and completely eliminated more intensively than in Escherichia coli cells. At thermoinduction the transposition of bacteriophage Mu cts62 into different chromosomal sites takes place, causing the induction of chlorate resistant and auxotrophic mutants with the frequency of 10(-4). Two clones deficient in production of 2 of the 4 resident prophages of Erwinia carotovora 268 strain were found among Mu-induced mutants. The deleted prophages are E105 and 59. DNA-DNA hybridization has revealed the complete and partial deletions of bacteriophage E105 with the level of L-asparaginase production in the cells remaining intact. The damage of the prophage 59 is probably caused by point mutations or short deletions.
Mol Gen Mikrobiol Virusol
PMID:[Mu-induced deletions and mutations of Erwinia carotovora chromosomes, including resident prophages E105 and 59]. 140 59

Human cell lines resistant to L-asparaginase or albizziin were isolated by multistep selection of HT1080 fibrosarcoma and MIA PaCa-2 pancreatic carcinoma cells. Mutants were cross-resistant to both drugs, but more resistant to the drug used for selection. The drug-resistant cell lines expressed elevated levels of asparagine synthetase activity and protein, up to 17-fold over that of the parental cells. Enzyme overproduction was due to gene amplification in the albizziin-resistant cells, whereas increased expression without amplification was observed in L-asparaginase-resistant cells.
Somat Cell Mol Genet 1990 Jan
PMID:Molecular and genetic characterization of human cell lines resistant to L-asparaginase and albizziin. 196 81

Most of L-asparaginase activity of Tetrahymena pyriformis was found to be present in microsomal membranes from which it has been purified to homogeneity (Tsirka, S.A.E. and Kyriakidis, D.A. Mol. Cell. Biochem. 83: 147-155, 1988). The native enzyme has a relative molecular weight of approximately 200 kDa, while under denaturing conditions the enzyme exhibits a subunit size of 39 kDa. Aminoacid analysis and an oligopeptide from N-terminal sequence have been determined. Dephosphorylation of L-asparaginase by alkaline phosphatase results in an activation of its catalytic activity. This enzyme also exhibits intrinsic phosphorylation activity with a Km value for ATP of 0.5 mM. Autophosphorylation with [gamma-32P] ATP of purified L-asparaginase results in the phosphorylation of tyrosine residues as well as in loss of its activity. Mg2+ and Ca2+ added together act synergistically to stimulate the kinase activity by more than 160%. The polyamines putrescine, spermidine and spermine activate the kinase approximately 100%, while neither cAMP or cGMP have any effect. These results indicate that this membrane protein with dual L-asparaginase/kinase activity must play an important role in regulating the intracellular levels of L-asparagine in Tetrahymena pyriformis.
Mol Cell Biochem 1990 Jun 01
PMID:L-asparaginase of Tetrahymena pyriformis is associated with a kinase activity. 211 26

Purified L-asparaginase of Tetrahymena pyriformis is a multi-subunit enzyme exhibiting protein kinase activity as well. The enzyme's L-asparaginase activity is affected by its phosphorylation state. Both native and dephosphorylated L-asparaginase show antiproliferative activity on three breast cancer cell lines (T47D, BT20 and MCF-7) and on Walker 256 cells. These cells do not possess measurable L-asparaginase or L-asparagine synthetase activity. When T47D cells are treated for different times with L-asparaginase and then placed in fresh medium, the growth of cells treated for 1, 3, or 6 hours is initiated and parallels control curve, while the growth of cells treated for 24 or 48 hours with L-asparaginase stays at the same inhibitory level (24 h treatment) or continues to drop (48 h treatment). Addition of D-asparagine, a competitive inhibitor of T. pyriformis L-asparaginase, counteracts the antiproliferative activity of L-asparaginase, indicating that L-asparaginase and not the kinase activity is responsible for that effect.
Mol Cell Biochem 1990 Aug 10
PMID:Antiproliferative activity of L-asparaginase of Tetrahymena pyriformis on human breast cancer cell lines. 212 95

A smooth decrease of the fluorescence emission polarization as the wavelength of registration increases along the emission spectrum was determined for some proteins and also for tryptophan, N-acetyl-tryptophan and glycyl-tryptophan. Various factors that can explain the way of the curve were analysed. A special attention was paid to the problem of the possibility of the 1Lb oscillator participation in the emission. It is shown that in the case of dual fluorescence emission from both 1La and 1Lb states the position and the shape of polarized components of emission spectrum and the magnitude of the ratio r320/r365, that characterizes the slope of the curve P = f(lambda em), must always depend upon lambda ex. Nevertheless it is shown that the dependences of r320/r365 upon lambda ex, found for some proteins are explained by the contribution of tyrosine residues into emission and there are no reasons to assume the participation of the 1Lb oscillator in the emission (even in the case of the proteins with shortwave spectrum position as L-asparaginase). It is shown that the slope of the curve in the case of individual emission centres is determined by the alteration of the electronic states between which the transition accompanied by the emission takes place. Heterogeneity of the fluorescence centres, that are to some or other extent inherent to proteins, also can influence the slope of the curve P = f (lambda em).
Mol Biol (Mosk)
PMID:[Polarization of intrinsic fluorescence of proteins. IV. Changes in the degree of polarization from the emission spectra]. 241 3

Of five amidohydrolase activities subject to nitrogen metabolite repression in Aspergillus nidulans, L-asparaginase shows clearest evidence of also being subject to repression by atmospheric oxygen. Such oxygen repressibility is only evident under nitrogen metabolite derepressed conditions. Asparaginase levels are also considerably elevated by areA300, an altered function allele of the positive acting wide domain regulatory gene areA mediating nitrogen metabolite repression and are drastically reduced by loss of function mutations in areA. A. nidulans has two L-asparaginase enzymes and it has been shown by the use of appropriate mutants that these regulatory effects are exerted on the expression of that specified by the ahrA gene but probably not that specified by the apnA gene.
Mol Gen Genet 1988 May
PMID:An asparaginase of Aspergillus nidulans is subject to oxygen repression in addition to nitrogen metabolite repression. 304 73

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.
Mol Cell Biochem 1988 May
PMID:Purification and properties of a membrane-bound L-asparaginase of Tetrahymena pyriformis. 313 90


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