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:4.1.2.13 (aldolase)
3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chemical synthesis of 4-hydroxy-2-ketopimelic acid is described. An aldolase that cleaves this compound to succinic semialdehyde and pyruvate has been purified from Acinetobacter grown at the expense of 4-hydroxyphenylacetic acid. The molecular weight of the enzyme was about 158,000 from sedimentation equilibrium data; other physical determinations gave values in reasonable agreement. The protein was globular and was dissociated in sodium dodecyl sulfate to give a species of molecular weight 25,700. The enzyme attacked both enantiomers of synthetic 4-hydroxy-2-ketopimelate and was stimulated by Mg(2+) and Mn(2+) ions.
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PMID:Purification and properties of 4-hydroxy-2-ketopimelate aldolase from Acinetobacter. 442 38

Chromatography of different soluble extracts from HeLa cells on poly(A)-Sepharose columns has allowed the isolation of a protein fraction eluted by 0.2 M NaCl and localized predominantly in the cytoplasmic supernatant and in the 0.5 M KCl ribosomal wash. This fraction is present in large amounts (around 3% of total cytosolic proteins) and appears to contain a major protein species that is acidic on electrofocusing (pI around 4.5) and phosphorylated. It runs on glycerol gradients and Sephadex G-200 chromatography close to the aldolase marker (158,000 daltons) and dissociates into apparently identical subunits of 38,000 +/- 2,000 daltons on sodium dodecyl sulfate-acrylamide gels, suggesting a tetrameric structure.
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PMID:Characterization of a protein species isolated from HeLa cell cytoplasm by affinity chromatography on polyadenylate-sepharose. 452 99

Two reactions in the catabolism of catechol by meta-fission, namely, hydration of 2-oxopent-4-enoate (vinylpyruvate) and aldol fission of the product, are catalyzed by stereospecific enzymes. The absolute configuration of this hydration product was shown to be l(S)-4-hydroxy-2-oxopentanoate. Vinylpyruvate hydratase, purified almost to homogeneity, had a molecular weight of about 287,000 and was dissociated in sodium dodecyl sulfate, without prior treatment with mercaptoethanol, into a species with an approximate molecular weight of 28,000. The hydratase was highly specific for its substrates; thus, although 2-oxo-cis-hex-4-enoate was also hydrated, structurally similar compounds such as the trans isomer, vinylacetic and crotonic acids, and the ring-fission products of catechol and methylcatechols were not attacked. Vinylpyruvate hydratase was activated by Mn(2+) ions. On the basis of these observations, a mechanism is proposed which closely resembles that for 4-hydroxy-2-oxopentanoate aldolase. A possible evolutionary connection between functionally related, divalent cation-activated hydro-lyases and aldolases is discussed. It was also demonstrated that l-(S)-4-hydroxy-2-oxohexanoate is the biologically active enantiomer of this hydroxy acid.
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PMID:Stereospecific enzymes in the degradation of aromatic compounds by pseudomonas putida. 469 Sep 69

Amidination of aldolase, glyceraldehyde-3-phosphate dehydrogenase, tryptophan synthetase B protein, L-arabinose isomerase, and the catalytic subunit of E. coli aspartate transcarbamylase with the bifunctional reagent dimethyl suberimidate produces cross-linked proteins, with reaction predominating within oligomers. Disc electrophoresis of a modified protein on polyacrylamide gel in the presence of sodium dodecyl sulfate resolves a set of species with molecular weights equal to integral multiples of the protomer molecular weight. For oligomers composed of identical protomers, the number of principal species observed is identical to the number of protomers in the oligomer. Application of the method to two proteins composed of dissimilar protomers, native aspartate transcarbamylase and tryptophan synthetase alpha(2)beta(2) complex of E. coli, revealed differences in the reactivities of the different kinds of protomer within each oligomer.
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PMID:Use of dimethyl suberimidate, a cross-linking reagent, in studying the subunit structure of oligomeric proteins. 491 6

Rats were injected with 1 mg of Zn2+ as zinc sulfate or 2 mg of Cd2+ as cadmium sulfate per kg of body weight on a daily basis. After seven injections, ferritin and metallothionein were isolated from the livers of the rats. Significant amounts of zinc were associated with ferritin. Incubation of such ferritin with apoenzymes of calf intestinal alkaline phosphatase, yeast phosphoglucomutase, and yeast aldolase restored their enzymic activity. The amount of zinc injected was insufficient to stimulate significant synthesis of metallothionein, but similar experiments with injection of cadmium did stimulate the synthesis of metallothionein. The amount of Zn2+ in ferritin of Cd-injected rats was greater than that in ferritin in Zn-injected rats, which was greater than that in ferritin of normal rats. Thus at comparable protein concentration ferritin from Cd-injected rats was a better Zn2+ donor than was ferritin from Zn-injected or normal animals. Ferritin is a normal constituent of several tissues, whereas metallothionein is synthesized under metabolic stress. Thus ferritin may function as a "metal storage and transferring agent" for iron and for zinc. It is suggested that ferritin probably serves as the initial chelator for Zn2+ and perhaps other metal ions as well and that under very high toxic levels of metal ions the synthesis of metallothionein is initiated as the second line of defense.
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PMID:Ferritin: a zinc detoxicant and a zinc ion donor. 621 27

The present work describes procedures in which seven major muscle enzymes and serum albumin can be simultaneously isolated from chicken skeletal muscles. The seven enzymes isolated were: phosphorylase, enolase, creatine-P kinase, aldolase, glyceraldehyde-3-P dehydrogenase, phosphoglycerate mutase, and triose-P isomerase. The proteins isolated by these methods were judged to be greater than 97% pure on the basis of electrophoretic analysis in sodium dodecyl sulfate polyacrylamide gels. The procedure is applicable for isolation of the enzymes from large (greater than 100 g) or small (less than 0.5 g) amounts of muscle tissue and the entire procedure can be completed within two days. Particularly useful features of the procedures are: (1) preferential solubilization of the enzymes from myofibrils by extraction of muscle specimens in solutions of different ionic strength; (2) specific precipitation of phosphorylase, creatine-P kinase, and glyceraldehyde 3-Phosphate dehydrogenase from solutions of specified pH and degrees of ammonium sulfate saturation; and (3) an alternate method for isolation of glyceraldehyde-3-P dehydrogenase by specific elution of the enzyme from phosphocellulose columns with ATP. Because of the ease, rapidity, and reproducibility of the procedures, these methods may be useful for the routine isolation of the muscle enzymes in studies on biochemical regulation, as well as for obtaining large quantitites of the enzymes for structural analysis.
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PMID:A simple procedure for the isolation of seven abundant muscle enzymes. 626 Dec 32

Intraperitoneal administration of leupeptin to rats induced a hemoglobin-hydrolyzing protease which was most active at pH 3.5 and was insensitive to pepstatin in various tissues such as the liver, kidney, and muscle, as observed previously in adult rat hepatocytes in primary culture (Tanaka, K., Ikegaki, N., and Ichihara, A. (1979) Biochem. Biophys. Res. Commun. 91, 102-107). The induced acidic protease was purified about 600-fold in 30% yield from rat liver by conventional chromatographic techniques. The purified enzyme appeared homogeneous by polyacrylamide gel electrophoresis in the presence or absence of sodium dodecyl sulfate and was a monomeric protein of Mr = 20,000. The enzyme appeared to be a glycoprotein because its induction was blocked by the addition of tunicamycin to cultures of hepatocytes and because the induced protease was absorbed on concanavalin A-Sepharose and eluted with methylglucoside. It seemed to be present in lysosomes and was fairly stable at various pH values and temperatures. It showed endopeptidase activity on various protein substrates, but scarcely hydrolyzed N-substituted derivatives of arginine. It did not hydrolyze esters, showed no aminopeptidase or carboxypeptidase activity, and did not inactivate glucose-6-phosphate dehydrogenase or aldolase. The enzyme appeared to be a thiol protease, since it was strongly inhibited by sulfhydryl-reactive compounds and N-( [N-(1-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl]-agmatine and was not inhibited by reagents specific for carboxyl-, serine-, or metalloproteases. This induced protease could be separated from cathepsins B, D, and H by chromatography. The enzyme was similar to cathepsin L in chromatographic behavior, Mr and pI, but differed from the latter in stability and in its inability to inactivate some enzymes. These results suggest that it differs from any known proteases found previously in rat liver.
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PMID:Purification and characterization of hemoglobin-hydrolyzing acidic thiol protease induced by leupeptin in rat liver. 637 Oct 12

The nature of the association of the glycolytic enzyme, aldolase, with mature bovine spermatozoa was investigated in comparison with bovine muscle aldolase. Bovine muscle aldolase (BMA) was optimally solubilized by 0.1% deoxycholate and purified to homogeneity by ammonium sulfate fractionation, gel-filtration chromatography and phosphocellulose affinity chromatography. Bovine sperm aldolase (BSpA) was solubilized with optimal specific activity by 0.1% Triton X-100 and 50 mM sodium phosphate. Soluble BSpA represented 10% of the total aldolase activity in bovine spermatozoa. It could not be purified from other sperm components by standard procedures. The association of BSpA with sperm components involved noncovalent, ionic and hydrophobic interactions and did not involve disulfide bonds or covalent bonds. The stability of the BSpA association with intracellular substructure implies that very specific multiple-ligand bonding is involved. The Km for fructose-1-phosphate (1.7 X 10(-1) M) was higher and the activity with fructose-1,6-biphosphate relative to fructose-1-phosphate (Vmax FBP/Vmax F-1-P = 0.038) was much lower than for either liver or muscle aldolase. Kinetic analysis and subcellular associations indicated that sperm aldolase is different from other isozymes of aldolase.
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PMID:Association of bovine sperm aldolase with sperm subcellular components. 646 57

The monoclinic crystalline form of aldolase from rabbit skeletal muscle grown at 29 degrees C is catalytically active in the direction of aldol cleavage. Activity was assayed for in a crystallization buffer containing 45% saturated ammonium sulfate using chemically unmodified single crystals cut to precise dimensions. Diffusion effects on velocities from assays employing aldolase crystals do not appear to be limiting when cut single crystals are crushed. Assays of crushed crystals are linear with respect to both time and enzyme concentration. Kinetic constants are reported for both substrates fructose 1-phosphate and fructose 1,6-phosphate. Maximal velocities and binding constants determined differ by no more than a factor of 2 between the crystalline and the soluble state of the enzyme. Analysis of the kinetic constants for fructose 1-phosphate as substrate shows that binding of substrate does not change in going to the crystalline state. Release of product is reduced roughly 2-fold in the crystalline state. A similar conclusion can be reached in the case of fructose 1,6-phosphate as substrate provided the "on" steps of substrate and product are only diffusion limited but independent of the physical state of the enzyme. It is not possible to distinguish between a more sluggish conformational change during catalysis or simply tighter product binding in the crystalline state as compared to the soluble enzyme state.
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PMID:Catalytic activity of rabbit skeletal muscle aldolase in the crystalline state. 646 60

Properties of newly synthesized crosslinking reagents (ACM) and their applications to proteins are studied (ACM is the abbreviation for a series of photoactivable and heterobifunctional crosslinking thiol reagents, each of which has two reactive groups, maleimide and azide). These reagents bind specifically to the sulfhydryl residues of proteins in the first reaction step. Upon photoactivation, the azide group of the coumarin ring reacts with side or main chains of the proteins, and thus intra- or intermolecular crosslinking can be elicited. In addition, the coumarin moiety of the reagents becomes highly fluorescent after photolysis. Therefore, the crosslinking products can be detected by fluorometry with high sensitivity in the pattern of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Reaction of ACM with rabbit muscle aldolase led to extensive crosslinking between subunits of the enzyme and maximally 25% of the total subunits were found to be crosslinked to the dimer.
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PMID:New fluorogenic, photoactivable, heterobifunctional crosslinking thiol reagents. 648 17


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