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)

Chronic sumithion toxicity in experimental crabs was induced by exposing them for 15 and 30 days to 0.04 ppm sumithion solution. The enzymes concerned with glycogenolytic metabolism (phosphorylase), glycolytic metabolism (aldolase), aerobic metabolism [succinate dehydrogenase (SDH), malate dehydrogenase (MDH)], anaerobic metabolism, lactate dehydrogenase (LDH) and alanine amino transaminase (AIAT)], were assayed in the muscle of control and experimental crabs. Glycogen, pyruvic acid, lactic acid were also estimated in the muscle of both control and experimental crabs. The muscle tissue of chronic sumithion-exposed crab exhibited suppressed glycogenolysis and glycolysis with an onset of gluconeogenesis. In general, chronic sumithion exposure seems to result in an elevation of the synthetic phase of muscle carbohydrate metabolism.
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PMID:Chronic sumithion toxicity: effect on carbohydrate metabolism in crab muscle. 682 35

Cathepsin D inactivated aldolase at pH values between 4.2 and 5.2; the chloride, sulphate or iodide, but not citrate or acetate, salts of sodium or potassium accelerated the rate of inactivation. Cathepsin D cleaved numerous peptide bonds in the C-terminus of aldolase, but the major site of cleavage in this region was Leu354-Phe355. The most prominent peptide products of hydrolysis were Phe-Ile-Ser-Asn-His-Ala-Tyr and Phe-Ile-Ser-Asn-His. Up to 20 amino acids were removed from the C-terminus of aldolase, but no further degradation of native aldolase was observed. By contrast, extensive degradation of the 40 000-Mr subunit was observed after aldolase was denatured. The cathepsin D-inactivated aldolase cross-reacted with antibodies prepared against native aldolase and had the same thermodynamic stability as native aldolase, demonstrated by differential scanning calorimetry and fluorescence quenching of tryptophan residues. Furthermore, the cathepsin-modified and native forms of aldolase were both resistant to extensive proteolysis by other purified cellular proteinases and lysosomal extracts at pH values of 4.8-8.0.
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PMID:Action of cathepsin D on fructose-1,6-bisphosphate aldolase. 688 56

Escherichia coli grown on gluconeogenic compounds as carbon sources produced two chemically and physically distinct types of fructose-1,6-biphosphate aldolases (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphatelyase, EC 4.1.2.13), while these bacteria produced only a single enzyme when grown on glucose or fructose. We have investigated this enzyme in several strains of Escherichia coli (Crookes, K-12, and B) grown on glucose, fructose lactate, pyruvate, alanine and glycerol by comparing chemical properties and mechanisms of action. Comparison of these mechanisms was accomplished by following the fate of 18O in the keto position of fructose 1,6-bisphosphate during the aldolase catalyzed cleavage reaction. The results show that the two enzymes have different mechanisms of action and are consistent with a Schiff-base mechanism for the one which was induced by gluconeogenic substrates and metal-chelate mechanism for the constitutive enzyme.
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PMID:Comparison of the mechanisms of two distinct aldolases from Escherichia coli grown on gluconeogenic substrates. 699 35

Dynamic examinations of the activity of glutamate-aspartate and glutamate-alanine aminotransferases (AST, ALT), fructose diphosphate aldolase and alkaline phosphatase in the cerebrospinal fluid (CSF) were carried out in 512 patients (14 groups) suffering from viral and bacterial meningitis in the acute period, as well as in reconvalescents. The activity of the CSF enzymes was also determined in 70 healthy subjects. It was found that in the acute period of meningitis the activity of the CSF enzymes (mostly of the aminotransferases) rose, this rise being greater in meningococcal and tuberculous meningitis than in the viral one. In reconvalescents the activity of the aminotransferases dropped, and that of aldolase and alkaline phosphatase got normal. The activity of the blood serum enzymes showed no substantial changes. The differences in the activity of the enzymes may serve as a criterion for diagnostic differentiation of meningitis.
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PMID:[Serum and cerebrospinal fluid enzyme spectra in meningitis and their differential diagnostic value]. 707 18

GLycolytic enzymes were studied from normal human retinas (both fetal and adult) and from retinoblastomas of eight patients and an established retinoblastoma cell line. No significant differences were found between the enzyme activities in the tissues investigated except for hexokinase and pyruvate kinase, which were significantly decreased in the tumor cells. In fetal retina, five different forms of pyruvate kinase could be detected by electrophoresis (K4, K3M, K2M2, KM3, and M4). In adult retina the K4 isozyme is almost absent, while in retinoblastoma the M4 isozyme is hardly present. In the retinoblastoma cell line, the M4 isozyme is completely absent. Alanine inhibition of pyruvate kinase from the retinoblastoma cell line is more inhibited compared to the pyruvate kinase of fetal retina and retinoblastoma and is even more inhibited compared to adult retina. Electrophoresis of aldolase from adult retina revealed the presence of all potential A-C hybrids (A4, A3C, A2C2, AC3, and C4). Fetal retina, however, is characterized by the predominance of the A type. The same patterns were observed in the retinoblastoma cell line and retinoblastoma. However, in other brain tumors, e.g., gliomas of adults, a five-membered A-C hybrid set is found. Electrophoresis of hexokinase from normal fetal and adult retina revealed the predominance of hexokinase type I; retinoblastoma and retinoblastoma cell line are both characterized by the presence of considerable amounts of hexokinase type II. The isozyme shifts in retinoblastoma result in an enzyme pattern identical to that of fetal retina except for the presence of hexokinase type II.
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PMID:Characterization of some glycolytic enzymes from human retina and retinoblastoma. 710 15

Ribonuclease A was introduced into the cytoplasm of IMR-90 human diploid fibroblasts by red cell-mediated microinjection. Early passage fibroblasts degraded ribonuclease A with a half-life of approximately 90 h in the presence of 10% fetal calf serum and enhanced the degradative rate 1.6-fold upon serum withdrawal. Senescent cells degraded ribonuclease A more slowly with half-lives ranging between 125 and 250 h and had diminished capacities to enhance the catabolism of this protein during serum starvation. Decreased protein degradation in senescent cells was also evident for microinjected RNase S-protein, RNase B, aldolase, lysozyme, and the synthetic copolymer polyglutamate: tyrosine:alanine (1:1:1). These alterations in the mechanisms and regulation of intracellular protein degradation may contribute to several biochemical abnormalities characteristic of aging cells and organisms.
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PMID:Altered degradation of proteins microinjected into senescent human fibroblasts. 717 58

The mechanism of degradation of fructose-1,6-bisphosphate aldolase from rabbit muscle by the lysosomal proteinase cathepsin B was determined. Treatment of aldolase with cathepsin B destroys up to 90% of activity with fructose 1,6-bisphosphate as substrate, but activity with fructose 1-phosphate is slightly increased. Cathepsin L, another lysosomal thiol proteinase, and papain are also potent inactivators of aldolase, whereas inactivation is not caused by cathepsins D or H even at high concentrations, or by cathepsin B inhibited by leupeptin or iodoacetate. The cathepsin-B-treated aldolase shows no detectable change in subunit molecular weight, oligomer molecular weight or subunit interactions. Cathepsin B cleaves dipeptides from the C-terminus of th aldolase subunits. Four dipeptides are released sequentially: Ala-Tyr, Asn-His, Ile-Ser and Leu-Phe, and a maximum of five additional dipeptides may be released. There are indications that this peptidyldipeptidase activity of cathepsin B may be an important aspect of its action on protein substrates generally.
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PMID:Degradation of fructose-1,6-bisphosphate aldolase by cathepsin B. 745 1

We report the construction of subunit interface mutants of rabbit muscle aldolase A with altered quaternary structure. A mutation has been described that causes nonspherocytic hemolytic anemia and produces a thermolabile aldolase (Kishi H et al., 1987, Proc Natl Acad Sci USA 84:8623-8627). The disease arises from substitution of Gly for Asp-128, a residue at the subunit interface of human aldolase A. To elucidate the role of this residue in the highly homologous rabbit aldolase A, site-directed mutagenesis is used to replace Asp-128 with Gly, Ala, Asn, Gln, or Val. Rabbit aldolase D128G purified from Escherichia coli is found to be similar to human D128G by kinetic analysis, CD, and thermal inactivation assays. All of the mutant rabbit aldolases are similar to the wild-type rabbit enzyme in secondary structure and kinetic properties. In contrast, whereas the wild-type enzyme is a tetramer, chemical crosslinking and gel filtration indicate that a new dimeric species exists for the mutants. In sedimentation velocity experiments, the mutant enzymes as mixtures of dimer and tetramer at 4 degrees C. Sedimentation at 20 degrees C shows that the mutant enzymes are > 99.5% dimeric and, in the presence of substrate, that the dimeric species is active. Differential scanning calorimetry demonstrates that Tm values of the mutant enzymes are decreased by 12 degrees C compared to wild-type enzyme. The results indicate that Asp-128 is important for interface stability and suggest that 1 role of the quaternary structure of aldolase is to provide thermostability.
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PMID:Subunit interface mutants of rabbit muscle aldolase form active dimers. 783

Lysine-146 of rabbit muscle aldolase (D-fructose-1,6-biphosphate aldolase, EC 4.1.2.13) is absolutely conserved in class I (Schiff base) aldolases and has been implicated previously in catalysis by protein modification. Site-directed mutagenesis was used to change lysine-146 to alanine, glutamine, leucine, or histidine, creating the mutant enzymes K146A, K146Q, K146L, and K146H, respectively. These mutant proteins were expressed at high levels in bacteria and were purified by substrate affinity elution from CM-Sepharose, the same method that is used for the wild-type enzyme. The mutants K146A, K146Q, and K146L had substrate cleavage rates below standard detection levels. Modified cleavage assays indicated that these enzymes were (0.5-2) x 10(6)-fold decreased in the rate of catalysis of fructose 1,6-bis(phosphate) (Fru-1,6-Pa)cleavage. The K146H enzyme, however, was approximately 2000-fold slower than wild type in the rates of both cleavage and condensation of Fru-1,6-P2. In assays for the presence of enzymatic intermediates, all of the mutant enzymes were able to catalyze formation of the carbanion intermediate with dihydroxyacetone phosphate, whereas this intermediate was below the level of detection with Fru-1,6-P2. Single-turnover experiments with these enzymes in excess over radiolabeled Fru-1,6-P2 were used to measure the rates of Schiff base and product formation. The rate of Schiff base formation was decreased in each of the mutant enzymes, yet the magnitude of this decrease was less than the reduction in the respective kcat. These mutations had a much larger effect, however, on the rate of C3-C4 bond breaking, showing that Lys-146 is crucial at this step of the catalytic cycle.
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PMID:Lysine-146 of rabbit muscle aldolase is essential for cleavage and condensation of the C3-C4 bond of fructose 1,6-bis(phosphate). 791 50

1. The generation of C2- and C3-deuterated L-lactate was monitored by 13C NMR in human erythrocytes exposed to D-[1-13C]glucose, D-[2-13C]glucose or D-[6-13C]glucose and incubated in a medium prepared in D2O. 2. The results suggested that the deuteration of the C1 of D-fructose 6-phosphate in the phosphoglucoisomerase reaction, the deuteration of the C1 of D-glyceraldehyde-3-phosphate in the sequence of reactions catalyzed by triose phosphate isomerase and aldolase and the deuteration of the C3 of pyruvate in the reaction catalyzed by pyruvate kinase were all lower than expected from equilibration with D2O. 3. Moreover, about 40% of the molecules of pyruvate generated by glycolysis apparently underwent deuteration on their C3 during interconversion of the 2-keto acid and L-alanine in the reaction catalyzed by glutamate-pyruvate transaminase. 4. The occurrence of the latter process was also documented in cells exposed to exogenous [3-13C]pyruvate. 5. This methodological approach is proposed to provide a new tool to assess in intact cells the extent of back-and-forth interconversion of selected metabolic intermediates.
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PMID:Generation of C3- and C2-deuterated L-lactic acid by human erythrocytes exposed to D-[1-13C]glucose, D-[2-13C]glucose and D-[6-13C]glucose in the presence of D2O. 800 54


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