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)

A procedure for the coupling at pH 7.2 of p-carboxy benzene diazonium chloride with rabbit muscle aldolase supported on phosphocellulose is described and some of the spectroscopic, structural and catalytic features of the material obtained are reported. The tetrameric azoenzyme is homogeneous in disc gel electrophoresis even in the presence of 8 M urea. Twelve molecules of the reactant are bound to the protein. Eight azocysteins are identified by both spectroscopic studies and amino acid analysis. The presence of one azohistidine is suggested by the spectroscopic data along with the presence of other, as yet unknown, chromophores. The azoaldolase shows unchanged catalytic properties using both D-fructose 1,6-bisphosphate and D-fructose 1-phosphate as substrates, as compared with the native enzyme. The pH profile of the enzyme activity is broadened towards the alkaline region but no changes occur in the physiological range of pH.
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PMID:Catalytically active azoaldolase. Preparation on solid support. 23 36

Bovine liver 2-oxo-4-hydroxyglutarate aldolase (suggested name: 2-oxo-4-hydroxyglutarate glyoxylate-lyase catalyzing the reaction: 2-oxo-4-hydroxyglutarate in equilibrium pyruvate + glyoxylate) contains eight to ten sulfhydryl groups as determined by titration of the enzyme with either 5,5'-dithiobis(2-nitrobenzoic acid) (Nbs2) or p-mercuribenzoate in the presence of 1% sodium dodecyl sulfate. In the absence of a denaturant, all of the cysteinyl residues react with p-mercuribenzoate whereas only four are accessible to titration with Nbs2. No differences in -SH group reactivity can be detected during titration of the aldolase with p-mercuribenzoate. In contrast, two classes of sulfhydryls can be differentiated in the disulfide exchange reaction with Nbs2 in the absence of a denaturant; one -SH group (Class I) reacts rapidly whereas three additional thiols (Class II) titrate at approx. 0.1 the rate of the Class I-SH residue. Both pyruvate and glyoxylate protect one of the three -SH residues in Class II from reaction with Nbs2. Either substrate also prevents titration of one to two thiol groups by p-mercuribenzoate and decreases the rate of reaction of aldolase -SH groups with Nbs2 in 8 M urea. These ligand-induced changes in -SH reactivity provide a sensitive indication that the enzyme exists in an altered conformational state in the presence of either of its cosubstrates. Titration of the enzyme with either Nbs2 or p-mercuribenzoate results in a progressive loss of aldolase activity which is not proportional to the number of -SH groups modified. The enzyme retains 50% of the activity of the native enzyme when Class I and Class II thiols (i.e. four -SH groups total) are modified with Nbs2; 15% residual activity is still observed following titration of all of the cysteinyl residues with p-mercuribenzoate. Pyruvate and glyoxylate provide partial protection against inactivation. It is concluded that inactivation of 2-oxo-4-hydroxyglutarate aldolase by Nbs2 or p-mercuribenzoate is a consequence of alterations in protein structure which accompany modification of -SH groups. The data argue against the direct participation of an active-site thiol group in the catalytic mechanism of 2-oxo-4-hydroxyglutarate aldolase, be that aldol cleavage and condensation or beta-decarboxylation.
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PMID:Sulfhydryl groups in relation to the structure and catalytic activity of 2-oxo-4-hydroxyglutarate aldolase from bovine liver. 55 45

The denaturation of aldolase from rabbit muscle in various solvents leads to significant qualitative and quantitative differences with respect to the structural disintegration of the enzyme. The differences refer to the quaternary structure and to the conformation which is changed only slightly in MgCl2 while in guanidine-HCl or urea at pH approximately 2 the molecule is close to the state of the random coil. Using the enzymic activity as a quantitative measure for the refolding process, the reaction order and the rate constants of the processes of structure formation (vi leads to N*) are found to be identical. This observation suggests a common intermediate D in the process of renaturation after denaturation and dissociation in the different solvent media. D may be considered an intermediate state with a defined number of nucleation centers whose rapid formation is predetermined by the aminoacid sequence. As taken from the first order kinetics in the given range of enzyme concentration, transconformation reactions are rate limiting in the obligatory pathway of refolding. At low enzyme concentrations second order steps gain importance which indicates that the enzymic activity is significantly modified by the formation of the native quaternary structure.
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PMID:Kinetics of reactivation of rabbit muscle aldolase after denaturation and dissociation in various solvent media. 90 15

Twenty-one patients developed acute renal failure in association with nontraumatic rhabdomyolysis and myoglobinuria. The illness followed an overdose of ethanol, heroin, or other depressant drug in 18 patients. Lethargy or coma was present in 17 patients and muscle swelling in 11. Evidence of rhabdomyolysis included markedly elevated creatine phosphokinase, myoglobinuria, and aldolase in blood. Initial biochemical findings were similar to those of acute renal failure due to other causes, but the abnormalities were exaggerated. There was a disproportionate rise in serum creatinine concentration in relation to serum urea nitrogen concentration. Profound hyperuricemia was present in most patients. Transient hypercalcemia developed during the diuretic phase in 5 patients. One patient died. We conclude that nontraumatic myoglobinuria with acute renal failure is not infrequent and may occur after an overdose of ethanol or heroin. The disease has good prognosis despite severe hypercatbolism and untreated profound hyperuricemia.
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PMID:Acute renal failure due to nontraumatic rhabdomyolysis. 93 19

Lysinuric protein intolerance (LPI), an autosomal recessive defect of diamino acid transport, is characterized chemically by renal hyperdiaminoaciduria, especially lysinuria, and by impaired formation of urea with hyperammonemia after protein ingestion. Our 20 patients thrived during breast-feeding, but ingestion of cow's milk caused diarrhea and vomiting. When able to select their diet, they rejected all protein-rich foods. They were short staturated and had weak atrophic muscles, osteoporosis, hepatomegaly and often splenomegaly. Four patients were mentally retarded. Fifteen patients had leukocyte counts below 4,000/mm3, and 17 patients had platelet counts below 150,000/mm3. Serum lactate dehydrogenase activity was constantly increased, and transaminase and aldolase activities were often increased. In the infants' livers, changes were only revealed by electron microscopy: increased and vesicular smooth endoplasmic reticulum, and abundance of glycogen particles in the hepatocytes. In the older patients, light microscopy demonstrated clearly limited areas where hepatocytes had large pale cytoplasm and small pyknotic nuclei. The diamino acids lysine, arginine and ornithine had plasma concentrations only one-third to one-half the normal mean; the renal clearances were clearly increased. Oral diamino acid loading tests suggested impaired intestinal absorption. Urea is built in the liver through transformation of ornithine to arginine, and cleavage of arginine to ornithine and urea. The addition of ornithine to an intravenous I-alanine loading prevented the hyperammonemia and normalized the urea production. Therefore, the diet has been supplemented with arginine, and more protein has been added. This therapy has lead to a remarkable catch-up growth in some patients. The pathophysiology of LPI is explained. Because of defective intestinal absorption and incrased renal loss, the diamino acids have a low plasma concentration. Their transport from plasma to hepatocytes is also impaired, and the liver becomes deficient in ornithine. This retards the urea cycle, and leads to postprandial hyperammonemia and protein aversion. The presence of the transport defect in the hepatocytes distinguishes LPI from other hyperdibasicaminoacidurias.
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PMID:Lysinuric protein intolerance. 115 80

Studied were the changes in the values of some hematologic indices (hemoglobin, erythrocytes, leukocites) as well as the values of some biochemical (total protein and protein fractions, urea, total lipids, bilirubin, inorganic, phosphorus calcium) and enzyme factors (lactatedehydrogenase, alkaline and acid phosphatase, aldolase, amino transferrases, creatinephosphokinase) in geese prior to and after experimental infection of Borrelia anserina. It was found that in the peak stage of spirochetemia the content of hemoglobin, total lipids, and calcium, the percent of albumins and alfa-globulins, and the activity of the alkaline phosphatase in the blood decreased. The prealbumin fraction of the serum protein was completely reduced. The activity of the lactatedehydrogenase, acid phosphatase, amino transferrases, and aldolase showed higher values that were statistically significant, while the activity of the creatinephosphokinase rose to a slighter extent. The urea, bilirubin, inorganic phosphorus, and the alfa-, beta-, and gamma-globulins correlated positively with the course of the infection.
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PMID:[Biochemical changes in the blood of geese infected with Borrelia anserina]. 117 37

The peptides released during the limited tryptic proteolysis of rabbit muscle aldolase (Biszku et al., 1973) were located in the primary structure. The pattern of peptide liberation, peptide bond splitting and activity decrease in compatible with two structural models for the truncated tetrameric product, named aldolase-T. According to the more probable model aldolase-T has the structure A+A+B++B++. Subunits B++ are deprived of the segments comprising residues 1-27, 42-71 and 306-364 of the intact enzyme and are inactive. The fragment comprising residues 28-41 is non-covalently attached to these subunits. Subunits A+ are depleted only of peptides 1-27 and 324-332 and retain 70% activity. In these subunits the fragment comprising residue 333-364 remains non-covalently bound. The molecular weights of the truncated subunits, determined with polyacrylamide-gel electrophoresis in the presence of sodium dodecylsulfate support the above conclusions. Aldolase-T can be reversibly denatured at pH 2 or in 4 M urea. The recovery of enzymatic activity after decreasing urea or acid concentration indicates the non-covalent rebinding of fragment 333-364. This fragment is named the "T-peptide" of trypsin-treated aldolase. It is suggested that segments 1-27 and 324-364 are not necessary for the renaturation process. Since aldolase-T is a tetramer it seems that large parts of the N- and C-terminal regions of the enzyme are not involved in the intersubunit interactions. The C-terminal region of aldolase, starting around residue 324, appears to be necessary to the structure of the active site. In contrast to this, the N-terminal region up to residue 27 and probably to residue 60, is not part of the active center.
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PMID:Some structural features of rabbit muscle aldolase as derived from its limited proteolysis. 121 Nov 2

Hybridization experiments with variants of an oligomeric protein often provide important information regarding subunit structure, function, and interactions. In some systems, however, the variants are so similar electrophoretically and chromatographically that purification of individual hybrids is not feasible. Therefore a method was developed for preparing hybrids by using 3,4,5,6-tetrahydrophthalic anhydride as a reversible acylating agent for protein amino groups. The technique involved acylating about 30% of the amino groups at pH 8 to give a derivative with a markedly altered net charge, formation of the hybrid set with unmodified and modified species, separation of the individual components by ion-exchange chromatography, and finally removal of the tetrahydrophthaloyl groups from the desired hybrid by incubation for about 1 day at pH 6 and room temperature. Experiments with model compounds and two enzymes showed that the anhydride was sepcific for amino groups. The extent of modification of proteins was measured by the spectral change at 250 nm, the loss of free amino groups, and the change in electrophoretic mobility of the polypeptide chains in polyacrylamide gels containing 8 M urea. Deacylation of modified, inactive aldolase and the catalytic subunit of aspartate transcarbamylase led to the restoration of the enzyme activity and electrophoretic mobility of the unmodified proteins. Both intra- and inter-subunit hybrids of aspartate transcarbamylase were prepared and isolated by using the tetrahydrophthaloyl groups as a reversible "chromatographic handle". Prior to deacylation the inter-subunit hybrid containing one acylated and one native catalytic subunit (and negative regulatory sub-units) exhibited no homotropic cooperativity and after deacylation the characteristic allosteric properties of the enzyme were regained. Similarly the ligand-promoted conformational changes associated with the allosteric transition were resotred upon deacylation of the intra-subunit hybrid containing one acylated and two native chains in each catalytic subunit. Criteria are described which must be satisfied if a reversible "chromatographic handle" is to be effective in hybridization experiments and it is shown that, despite some heterogeneity in its reaction with protein amino groups, 3,4,5,6-tetrahydrophthalic anhydride shows considerable promise for studies of oligomeric proteins.
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PMID:A method for the separation of hybrids of chromatographically identical oligomeric proteins. Use of 3,4,5,6-tetrahydrophthaloyl groups as a reversible "chromatographic handle". 124 10

A comparison was made in the blood levels of various cell types and biochemical substances and in lymphocyte antigens between 107 healthy sheep from a flock contaminated with scrapie (HC sheep) and 93 sheep from a noncontaminated flock (NC sheep), which served as a control population. Significant differences between the two groups of sheep were found in some of the levels, as had previously been found with lymphocyte antigens. The HC sheep, which included genetically resistant animals, could be distinguished from the NC sheep by their lower levels of various white cells, a noticeable decrease in urea, a moderate decrease in Mg2+ and Mn2+ ions, beta- and gamma-globulins, serotonin and vitamin B12, a strong increase in uric acid and a moderate increase in K+, Cl-, HCO3-, Zn2+, and Al3+ ions, as well as in total lipids and in the albumin to globulin ratio. In this HC population, the only enzyme with an increased level was aldolase; the levels of the other 7 enzymes measured were lowered. The observed modifications were considered to be signs of latent disturbances in the leukocyte system and in hepatic and renal functions, in spite of apparent resistance. Eleven lymphocyte antigens were studied. These antigens are not independent of the blood levels of the various substances measured, but are often correlated in a statistically significant manner with some of them. In the HC sheep, the lymphocyte antigens correlated with the modified levels in the blood were different from those in the control population.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diverse biological parameters in clinically healthy sheep from a flock with scrapie: variations, and correlations with OLA antigens. 148 54

Experiments on 156 rats maintained at ration with copper deficiency have demonstrated a decrease in the values of iodine metabolism in organs and tissues excluding the liver where a sharp increase in the concentration and content of inorganic iodine was observed. A disturbance in indices of carbohydrate and proteins metabolism in the organism of animals is marked. A direct relationship with a correlation coefficient equaling 0.87-1.00 is determined between changes in the concentration of protein-bound iodine in blood and concentration of glycogen in the liver, skeletal muscles, albumins, alpha 1-, alpha 2-globulins, urea concentration; an inverse relationship with glucose, activity of blood lipo-dehydrogenase and liver mitochondria, aldolase, concentration of pyruvic and lactic acids is established as well. It is concluded that copper deficiency can exert both a direct effect on metabolic processes (as data from literature testify) and an indirect one disturbing iodine metabolism, i. e. sharply decreasing protein-bound iodine production by the thyroid gland.
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PMID:[The effect of copper on the metabolism of iodine, carbohydrates and proteins in rats]. 169 3


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