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)

1. Seven unique carboxymethylcysteine-containing peptides have been isolated from tryptic digests of rabbit muscle aldolase carboxymethylated with iodo[2-(14)C]acetic acid in 8m-urea. These peptides have been characterized by amino acid and end-group analysis and their location within the cyanogen bromide cleavage fragments of the enzyme has been determined. 2. Reaction of native aldolase with 5,5'-dithiobis-(2-nitrobenzoic acid), iodoacetamide and N-ethylmaleimide showed that a total of three cysteine residues per subunit of mol.wt. 40000 were reactive towards these reagents, and that the modification of these residues was accompanied by loss in enzymic activity. Chemical analysis of the modified enzymes demonstrated that the same three thiol groups are involved in the reaction with all these reagents but that the observed reactivity of a given thiol group varies with the reagent used. 3. One reactive thiol group per subunit could be protected when the modification of the enzyme was carried out in the presence of substrate, fructose 1,6-diphosphate, under which conditions enzymic activity was retained. This thiol group has been identified chemically and is possibly at or near the active site. Limiting the exposure of the native enzyme to iodoacetamide also served to restrict alkylation to two thiol groups and left the enzymic activity unimpaired. The thiol group left unmodified is the same as that protected by substrate during more rigorous alkylation, although it is now more reactive towards 5,5'-dithiobis-(2-nitrobenzoic acid) than in the native enzyme. 4. Conversely, prolonged incubation of the enzyme with fructose 1,6-diphosphate, which was subsequently removed by dialysis, caused an irreversible fall in enzymic activity and in thiol group reactivity measured with 5,5'-dithiobis-(2-nitrobenzoic acid). 5. It is concluded that the aldolase tetramer contains at least 28 cysteine residues. Each subunit appears to be identical with respect to number, location and reactivity of thiol groups.
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PMID:The reactivity of thiol groups and the subunit structure of aldolase. 542 37

The specific activities of glutathione reductase (GR), EC 1.6.4.2, and aldolase, (ALD) EC 4.1.2.13, were determined in the homogenates of 60 cataractous lenses. Concentrations of certain plasma constituents and the morphological types of cataract of the patients were known. Investigations were aimed at establishing a possible correlation between enzyme activities and plasma constituents as well as between the specific activities of GR and ALD and type of cataract. A correlation between the specific activity of GR and the urea content of the blood could be identified. Results also indicated a relationship between the decrease in GR activity and the formation of cortical cataracts.
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PMID:Studies of lens enzyme activities in relation to cataract type and plasma constituents. 641 62

Two different isoenzymes of fructose-P2 aldolase can be resolved by chromatography of crude spinach leaf extracts on DEAE-cellulose columns. The acidic isoenzyme comprises about 85% of the total leaf aldolase activity. The two forms differ in primary structure as judged by their distinctive amino acid compositions, tryptic peptide patterns, and immunological properties. Only the acidic isoenzyme was detected in extracts of isolated chloroplasts, suggesting that this molecule represents the chloroplast form of spinach leaf aldolase while the basic isoenzyme is of cytosolic origin. The cytosolic (basic) isoenzyme and chicken aldolase A4 are similar in the following respects. 1) They have similar specific catalytic activity (10-15 units/mg); 2) they are both highly sensitive to inactivation by very limited digestion with bovine pancreatic carboxypeptidase A; 3) they both have subunit molecular weights of 40,000; 4) they both have derivatized (blocked) NH2-terminal structures; 5) they are both resistant to thermal denaturation at 50 degrees C; and 6) they both regain catalytic activity following reversible denaturation at pH 2.3 or in 5.8 M urea. Also, the cytosolic aldolase cross-reacted immunologically with the single aldolases present in spinach seeds and in wheat germ. Further, this isoenzyme readily "hybridized" with chicken aldolase A4 in vitro. These observations demonstrate the close homology between the cytosolic aldolases derived from plant and animal origins. The chloroplast aldolase had a specific catalytic activity of about 8 units/mg and, like its cytosolic counterpart, was severely inactivated by limited digestion with carboxypeptidase A. However, this isoenzyme was distinct from the cytosolic aldolase in the following characteristics: 1) its "small" subunit size (Mr congruent to 38,000); 2) its underivatized NH2-terminal structure; 3) its high sensitivity to thermal denaturation at 50 degrees C; and 4) its inability to refold into an enzymatically active conformation following denaturation at pH 2.3 or in 5.8 M urea. The distinctive properties of the chloroplast aldolase may be expected for an enzyme which is synthesized as a higher molecular weight precursor on cytosolic polysomes and is then proteolytically processed to the "mature" form during its migration into the chloroplast organelle.
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PMID:Isolation and characterization of the cytosolic and chloroplast forms of spinach leaf fructose diphosphate aldolase. 642 Mar 97

Using a highly sensitive "subunit exchange" assay, we have studied the relative strengths of interactions between different subunit types (A and C) of fructosediphosphate aldolase and have determined the mode of dissociation of aldolase tetramers in vitro. Interactions between C subunits within C4 tetramers were found to be considerably more resistant to disruption than were interactions between A subunits in A4 tetramers with regard to increasing concentrations of H+, OH-, or urea. Slight dissociation of A4 was also observed in 1.2 M magnesium chloride. These observations suggest that the quaternary structure of aldolase C4 is inherently more stable than that of aldolase A4. Also, the symmetrical heterotetramer A2C2 was found to be more resistant to urea-mediated dissociation than was the aldolase A4 homotetramer; this observation suggests that, even when in heteromeric combination, C subunits have a stabilizing influence on the quaternary structure of aldolase tetramers. In no case did we find evidence for a stable dimeric intermediate in the dissociation of aldolase tetramers to monomers. These observations are considered in terms of the tetrahedral arrangement of subunits in the aldolase tetramer. The general applicability of the subunit exchange assay described here for studying the subunit structure and mode of dissociation of oligomeric enzymes is discussed.
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PMID:Stability of quaternary structure and mode of dissociation of fructosediphosphate aldolase isoenzymes. 650 21

A study was made of solubilization of aldolase isolated from homogenates of skeletal muscles, both intact and being in the state of contracture due to urea action. Compared to water, electrolytes extract more aldolase from homogenates of intact and altered muscles. Almost the same amounts of aldolase were extracted with electrolytes from homogenates of muscles, which lost irreversibly their excitability, and of intact muscles. The actomyosin isolated from muscles displayed aldolase activity not removed under reprecipitation. The aldolase activity of actomyosin, the increase in sorption activity of proteins due to their conformational changes, and the decrease in excitability of aldolase isolated from homogenates of altered muscles by urea doses inducing denaturation of actomyosin and aldolase, all this may suggest that the action of injured agents on muscle stimulates the ability of aldolase and actomyosin to interact. The ratio of free and bound forms of aldolase differs in the intact and in the altered muscle cell.
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PMID:[Nature of the changes in water-soluble enzyme activity in the action of injurious agents on the muscles. II. The change in the extractability of aldolase from muscles exposed to urea]. 660 56

Some experimental and clinical studies were done from the metabolic viewpoint to elucidate the characteristics of myonephropathic-metabolic syndrome. In experimental dogs with their femoral arteries ligated and two third of femoral muscles divided, aldolase and myoglobin showed remarkable increase without significant changes in electrolytes. Slight increase of GPT and GOT was observed. Amino acids showed elevation in urea, taurin, leucin, isoleucin, valine, threonine, 3-methylhistidine, phenylalanine, histidine, lysine, methionine, tyrosine and anserin and decrease in glutamine, alanine, glycine, proline, carnosine, citrullin and arginine. In patients with acute arterial occlusion, potassium, GOT, LDH, CPK, lactate and pyruvate increased moderately and myoglobin showed remarkable increase and aldolase slight increase. Amino acids showed remarkable increase in 3-methylhistidine and beta-amino-isobutyric acid and moderate increase in phenylalanine and arginine. These results revealed that measurement of free amino acid concentration, especially that of methylhistidine as well as myoglobin, pyruvate, lactate and some other enzymes might be of great help to predict the prognosis of patients with acute arterial occlusion of the extremities.
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PMID:[Metabolic study on acute arterial occlusion of the extremities]. 667 89

Hereditary fructose intolerance is due to a deficiency of liver aldolase (aldolase B). Little is known about its molecular mechanisms. We have tried to demonstrate the presence of the molecule and have explored the possibility of genetic heterogeneity. Liver samples from fifteen cases of hereditary fructose intolerance due to aldolase B deficiency were studied by various electrophoretic techniques. After electrophoresis on polyacrylamide gels, proteins were electrophoretically transferred on to nitrocellulose filters. They were treated with specific antialdolase B antibodies, and then with radioiodinated protein A, followed by autoradiography. Investigations included: (a) sodium dodecyl sulphate electrophoresis, in order to detect the presence of immunologically reactive molecules and to estimate the subunit size; (b) attempts to discover charge anomalies of the native molecule and of its subunits, by the use of: Isoelectric focusing of the native enzyme. Isoelectric focusing and non-equilibrium pH gradient electrophoresis (NEPHGE) after dissociation in urea. The major results were the following: (1) In all cases a cross-reacting material was found, with a molecular subunit size of 38000, indistinguishable from that of controls. (2) Evidence for molecular heterogeneity of the disease was provided by two types of data: amount of apparent immunologically reactive protein, which varied from less than 3% to 100% of that of controls; and charge data, aldolase B from seven patients showing an increased negative charge and from one patient a normal charge.
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PMID:Molecular studies of liver aldolase B in hereditary fructose intolerance using blotting and immunological techniques. 676 Jul 89

Stability of lactatedehydrogenase (LDG) and glucose-6-phosphate dehydrogenase (G-6-PhDG) to the action of heating and urea on the muscle and on the enzymes isolated from muscle was studied. By the stability to the thermal agent in the system of the muscle and out of it LDG and G-6-PhDG exceed creatine kinase and aldolase; the most thermostable enzyme is G-6-PhDG. According to the action of urea on the muscle G-6-PhDG is the most stable enzyme, LDG is the most labile one among the studied enzymes. Under the action of urea on the isolated enzymes G-6-PhDG is the most labile one.
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PMID:[Effect of urea and heating on lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity]. 709 15

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

We recently developed a single photon radioluminescence (SPR) technique to measure submicroscopic distances in biological samples [Bicknese et al., and Shahrokh et al., Biophys. J., 63 (1992) 1256-1279]. SPR arises from the excitation of a fluorophore by the energy deposited from a slowing beta decay electron. The purpose of this study was to detect 3H2O molecules near tryptophan residues in proteins by tryptophan SPR. To detect small SPR signals, a sample compartment with reflective ellipsoidal optics was constructed, and amplified signals from a cooled photomultiplier were resolved by pulse-height analysis. A Monte Carlo calculation was carried out to quantify the relationship between SPR signal and 3H2O-tryptophan proximity. Measurements of tryptophan SPR were made on aqueous tryptophan; dissolved melittin (containing a single tryptophan); native and denatured aldolase; dissolved aldolase, monellin, and human serum albumin; and the integral membrane proteins CHIP28 (containing a putative aqueous pore) and MIP26 using 3H2O or the aqueous-phase probe 3H-3-O-methylglucose (OMG). After subtraction of a Bremsstrahlung background signal, the SPR signal from aqueous tryptophan (cps.microCi-1 mumol-1 +/- SE) was 8.6 +/- 0.2 with 3H2O and 7.8 +/- 0.3 with 3HOMG (n = 8). With 3H2O as donor, the SPR signal (cps.microCi-1 mumol-1) was 9.0 +/- 0.3 for monomeric melittin in low salt (trytophan exposed) and 4.6 +/- 0.8 (n = 9) for tetrameric melittin in high salt (tryptophans buried away from aqueous solution). The ratio of SPR signal obtained for aldolase under denaturing conditions of 8 M urea (fluorophores exposed) versus non-denaturing buffer (fluorophores buried) was 1.53 +/- 0.07 (n = 6). Ratios of SPR signals normalized to fluorescence intensities for monellin, aldolase, and human serum albumin, relative to that for d-tryptophan, were 1.42, 1.09, and 1.04, indicating that the cross-section for excitation of fluorophores in proteins is greater than that for tryptophan in solution. For the CHIP28 and MIP26 proteins in membranes, the ratio of SPR signal obtained with 3H2O versus 3HOMG was 1.35 +/- 0.13 (CHIP28, n = 5) and 0.99 +/- 0.02 (MIP26). These data are consistent with the existence of an aqueous channel through CHIP28 that excludes small solutes. We conclude that tryptophan radioluminescence in proteins is measurable and provides unique information about the presence of local aqueous compartments.
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PMID:Detection of water proximity to tryptophan residues in proteins by single photon radioluminescence. 774 62


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