Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.2.13 (aldolase)
 3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1) A lysosomal protease, a new cathepsin that inactivates glucose-6-phosphate dehydrogenase [EC 1.1.1.49] and some other enzymes and differs from cathepsin B [EC 3.4.22.1] was purified about 2,200-fold from crude extracts of rat liver by cell-fractionation, freezing and thawing, acetone treatment, gel filtration, and DEAE Sephadex and CM-Sephadex column chromatographies. 2) The new cathepsin was markedly activated by the thiol-reagent, 2-mercaptoethanol and inhibited by monoiodoacetate. 3) The molecular weight of the new cathepsin was found by Sephadex G-75 column chromatography to be 22,000, which is smaller than that of cathepsin B. 4) The optimum pH of the enzyme for inactivation of glucose-6-phosphate dehydrogenase was pH 5.0--5.5. The enzyme was unstable in alkali and on heat treatment. 5) The rates of inactivation of glucose-6-phosphate dehydrogenase, apo-ornithine aminotransferase [EC 2.6.1.13], apo-tyrosine aminotransferase [EC 2.6.1.5], apo-cystathionase [EC 4.4.1.1], glucokinase [EC 2.7.1.2], glyceraldehyde-3-phosphate dehydrogenase [EC 1.2.1.12], and malate dehydrogenase [EC 1.1.1.37] by the new cathepsin were higher than those by cathepsin B. However aldolase [EC 4.1.2.13] was inactivated more rapidly by cathepsin B than by the new cathepsin. Lactate dehydrogenase [EC 1.1.1.27], glutamate dehydrogenase [EC 1.4.1.2] and alcohol dehydrogenase [EC 1.1.1.1] were not inactivated by either cathepsin. Unlike cathepsin B, the new cathepsin scarcely hydrolyzes N-substituted derivatives of arginine.
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PMID:Purification and properties of a new cathepsin from rat liver. 3 59

2-Keto-4-hydroxyglutarate aldolase, which catalyzes the reversible cleavage of 2-keto-4-hydroxyglutarate, yielding pyruvate plus glyoxylate, has been purified from extracts of bovine kidney to apparent homogeneity as judged by polyacrylamide gel electrophoresis, gel filtration chromatography, sucrose density gradient centrifugation, and meniscus depletion sedimentation equilibrium experiments. The enzyme from this source has a native and a subunit mass of 144 and 36 kDa, respectively; the pH-activity optimum is 8.8. Rather than being stimulated, aldolase activity is inhibited to varying degrees by added divalent metal ions, whereas a number of metal ion-chelating agents have no effect. An absolute requirement for added thiol compounds could not be shown, but 2-mercaptoethanol enhances activity 2-fold, and added Hg2+ as well as p-mercuribenzoate or dithiodipyridine markedly inhibit catalysis. Incubation of the enzyme with either pyruvate or glyoxylate in the presence of NaBH4 causes extensive loss of aldolase activity concomitant with stable binding of approximately 1.0-1.5 mol of 14C-labeled substrate/mol of enzyme. The circular dichroism spectrum for native aldolase is characteristic of an alpha-helix; incubation of the enzyme with glyoxylate has no effect on this spectrum, but it is considerably altered by pyruvate. Bovine kidney aldolase shows no stereospecificity in catalyzing the aldol cleavage of the two optical isomers of 2-keto-4-hydroxyglutarate, and although it also catalyzes the beta-decarboxylation of oxalacetate, its decarboxylase/aldolase activity ratio is lower than that seen with the pure enzyme from either bovine liver or Escherichia coli.
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PMID:2-Keto-4-hydroxyglutarate aldolase: purification and characterization of the homogeneous enzyme from bovine kidney. 158 31

The nature of binding of FDP aldolase to bovine erythrocyte membrane was examined. The Km value of bound and soluble enzyme differed by an order. The absence of time-lag in the velocity-time curves at various concentrations of the substrate and the similar extent of inactivation of bound and soluble enzyme on heat treatment suggested that the enzyme was bound at a point other than the catalytic site. The release of the enzyme by various glycolytic intermediates suggested their involvement in binding to the catalytic site through phosphate linkage. The non-phosphorylated compounds like lactate, reduced glutathione, 2-mercaptoethanol and EDTA were ineffective in eluting the enzyme. On the basis of separate binding sites on the enzyme for membrane and ligands, the mechanism of association dissociation of aldolase has been suggested.
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PMID:Mechanism of aldolase binding to erythrocyte membrane: Part II. Kinetic aspects. 667 17

A metallo-endoproteinase was purified from mouse kidney. The enzyme was solubilized from the 100 000 g sediment of kidney homogenates with toluene and trypsin, and further purified by fractionation with (NH4)2SO4. DEAE-cellulose chromatography and gel filtration. The molecular weight of the metalloproteinase was estimated by gel filtration on Sepharose 6B to be 270 000--320 000. On sodium dodecyl sulphate/polyacrylamide-gel electrophoresis in the presence of 2-mercaptoethanol, a single major protein with a mol.wt. of 81 000 was observed. Thus the active enzyme is an oligomer, probably a tetramer. It is a glycoprotein and has an apparent isoelectric point of 4.3. Kidney homogenates and purified preparations of the metalloproteinase degraded azocasein optimally at pH 9.5 and at I 0.15--0.2. The activity was not affected by inhibitors of serine proteinases (di-isopropyl phosphorofluoridate, phenylmethanesulphonyl fluoride), cysteine proteinases (4-hydroxymercuribenzoate, iodoacetate), aspartic proteinases (pepstatin) or several other proteinase inhibitors from actinomycetes (leupeptin, antipain and phosphoramidon). Inhibition of the enzyme was observed with metal chelators (EDTA, EGTA, 1,10-phenanthroline), and thiol compounds (cysteine, glutathione, dithioerythritol, 2-mercaptoethanol). The metalloproteinase degraded azocasein, azocoll, casein, haemoglobulin and aldolase, but showed little or no activity against the synthetic substrates benzoylarginine 2-naphthylamide, benzoylglycylarginine, benzyloxycarbonylglutamyltyrosine or acetylphenylalanyl 2-naphthyl ester. This metalloproteinase from mouse kidney appears to be distinct from previously described kidney proteinases.
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PMID:Purification and characterization of a metallo-endoproteinase from mouse kidney. 704 88

Fructose 1, 6-biphosphate aldolase from Ceratitis capitata is a tetramer of identical subunits with 34% alpha-helix, 22% beta structure and 44% of aperiodic order. Increase of urea concentration up to 4.0 M results in non-cooperative reversible dissociation of the enzyme. Sodium dodecylsulphate 0.06% (w/v) dissociates the tetramer cooperatively with retention of the helical content. Thermal denaturation was a non-reversible cooperative process with a midpoint for the transition at 55 degrees. Cysteine residues are involved in this process and 2-mercaptoethanol preserves partially the enzyme activity. The acidic dissociation of the enzyme is a non-reversible process in contrast to the reversible basic dissociation. Increase of ionic strength results in a more ordered secondary structure for the monomer after acidic dissociation.
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PMID:Conformational stability of fructose-1, 6-biphosphate aldolase from Ceratitis capitata. 730 59

The state of post-translational modification of the class-II fructose-1,6-bisphosphate aldolase (FBP-aldolase) purified from Escherichia coli was examined by electrospray ionisation mass spectrometry (ESI-MS). The mass was larger than that expected from the known DNA sequence by approximately 80 +/- 6 Da, suggesting the presence of a covalent modification on the protein. Phosphorylation (+ 80 Da), a known modification in an FBP-aldolase from Bacillus subtilis and a suspected modification in this E. coli aldolase, was ruled out as the extra mass was readily removed by treatment with dithiothreitol. Purification of aldolase by a protocol which omitted 2-mercaptoethanol from all buffers resulted in the purified protein having the expected mass (39016 Da). The extra mass was therefore established as a covalent adduct of the protein with 2-mercaptoethanol (+ 76 Da). Reduction and alkylation studies, followed by isolation of tryptic peptides, established that the site of attachment was Cys36. Although no significant effect of the modification on the activity of the protein was observed, the study underlines the ease with which a protein can be modified covalently by a simple and mild purification procedure; such labelling, which may not always be benign, would be undetectable without the routine use of mass spectrometric analysis.
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PMID:A reactive, surface cysteine residue of the class-II fructose-1,6-bisphosphate aldolase of Escherichia coli revealed by electrospray ionisation mass spectrometry. 785 30