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

---

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

The adsorption of aldolase to myofibrils derived from rabbit skeletal muscle has been investigated by partition equilibrium studies at pH 6.8, I = 0.158 M, and the results interpreted in terms of an intrinsic association constant of 410,000 M-1 for the interaction of four sites on aldolase with myofibrillar sites, there being one such site for every 10-12 heptameric repeat units of F-actin-tropomyosin-troponin thin filament. Involvement of the active site of the enzyme in the adsorption process is indicated by the fact that competitive inhibition of the phenomenon by phosphate may be accounted for by an intrinsic association constant of 400 M-1 for the aldolase-phosphate interaction, a value in good agreement with that describing phosphate inhibition of the enzymatic hydrolysis of fructose-1,6-bisphosphate under similar conditions. On the basis of these equilibrium constants plus the aldolase and thin filament contents of muscle, resting muscle is indicated as containing a significant proportion (25-30%) of aldolase in the bound form, with changes in the subcellular distribution of the enzyme being likely during exercise due to the increased concentrations of Ca2+ and fructose-1,6-bisphosphate that then prevail.
...
PMID:Equilibrium partition studies of the interaction between aldolase and myofibrils. 661 29

The interactions of aldolase with regulatory proteins of rabbit skeletal muscle were investigated by moving-boundary electrophoresis. A salt-dependent interaction of troponin, tropomyosin and the tropomyosin-troponin complex with aldolase was detected, the tropomyosin-troponin complex displaying a greater affinity for the enzyme than did either regulatory protein alone. The results indicate that aldolase possesses multiple binding sites (three or more) for these muscle proteins. Quantitative studies of the binding of aldolase to actin-containing filaments showed the interaction to be influenced markedly by the presence of these muscle regulatory proteins on the filaments. In imidazole/HCl buffer, I 0.088, pH 6.8, aldolase binds to F-actin with an affinity constant of 2 x 10(5) M-1 and a stoicheiometry of one tetrameric aldolase molecule per 14 monomeric actin units. Use of F-actin-tropomyosin as adsorbent results in a doubling of the stoicheiometry without significant change in the intrinsic association constant. With F-actin-tropomyosin-troponin a lower binding constant (6 x 10(4) M-1) but even greater stoicheiometry (4:14 actin units) are observed. The presence of Ca2+ (0.1 mM) decreases this stoicheiometry to 3:14 without affecting significantly the magnitude of the intrinsic binding constant.
...
PMID:Binding of aldolase to actin-containing filaments. Evidence of interaction with the regulatory proteins of skeletal muscle. 689 70

Electron micrographs of the paracrystals formed when fructose bisphosphate aldolase (EC 4.1.2.13) is added to actin-containing filaments were analysed by computer methods so that ultrastructural changes could be correlated with the various stoicheiometries of binding determined in the preceding paper [Walsh, Winzor, Clarke, Masters & Morton (1980) Biochem. J. 186, 89-98]. Paracrystals formed with aldolase and either F-actin or F-actin-tropomyosin have a single light transverse band every 38 nm, which is due to aldolase molecules cross-linking the filaments. In contrast, the paracrystals formed between aldolase and F-actin-tropomyosin-troponin filaments show two transverse bands every 38 nm: a major band, interpreted as aldolase binding to troponin, and a minor band, interpreted as aldolase cross-linking the filaments. The intensity of the minor band varies with Ca2+ concentration, being greatest when the Ca2+ concentration is low. A model for the different paracrystal structures which relates the various patterns and binding stoicheiometries to structural changes in the actin-containing filaments is proposed.
...
PMID:Interaction of aldolase with actin-containing filaments. Structural studies. 689 71

Homogenates of the posterior latissimus dorsi muscle, a phasic muscle, were fractionated by a one-step zonal centrifugation technique into four major organelle populations and cytoplasmic constituents. These were: (1) Plasma membrane fragments with a modal equilibrium density of 1.10 and containing 5'-nucleotidase, alkaline phosphodiesterase, p-nitrophenylphosphatase and acid phosphatase (beta-glycerophosphate was used as the substrate). (2) Sarcoplasmic reticular fragments which could be further subdivided into calcium transport vesicles, with a model equilibrium density of 1.16, that exhibited calcium uptake; K+-ATPase; leucyl-bet-naphthylamidase; acid phosphodiesterase; acid phosphatase (using cytidine monophosphate as the substrate); and sarcoplasmic reticular lysosomes, with a model equilibrium density of 1.18, possessing dipeptidyl-aminopeptidase II, cathepsin D, alpha-glucosidase, N-acetyl-beta-glucosaminidase, and NADH oxidase activity. (3) Mitochondria with a modal equilibrium density of 1.21. (4) Catalase-containing vesicles with a modal equilibrium density of 1.22; and cytoplasmic constituents (modal density of 1.25) with phosphorylase, pyruvate kinase, myosin-ATPase, aldolase, and protein and RNA content. The purity of these organelles was equal to or better than previous efforts, with a 30-fold purification achieved for 5'-nucleotidase and alkaline phosphodiesterase. These results lend support to the hypothesis that the sarcoplasmic reticulum of phasic muscle, in addition to its specialized role in excitation-contraction coupling, represents a multifunctional membrane system, and that, similar to the smooth endoplasmic reticulum of other cells, it includes some membrane-bound lysosomal enzymes and NADH oxidase.
...
PMID:Isopycnic-zonal centrifugation of plasma membrane, sarcoplasmic reticular fragments, lysosomes, and cytoplasmic proteins from phasic skeletal muscle. 721 87

Previously reported results of equilibrium-partition experiments on the interaction of aldolase with actin-containing filaments [Walsh, Winzor, Clarke, Masters & Morton (1980) Biochem. J. 186, 89-98] have been subjected to a more rigorous theoretical analysis involving consideration of the consequences of cross-linking interactions between enzyme and filament. The experimental results obtained with F-actin-tropomyosin are best described by a model with one binding site per heptameric repeat unit of filament and a value of 39000 M-1 for the site binding constant, k. Similar analyses of the influence of Ca2+ on aldolase binding to F-actin--tropomyosin--troponin substantiate the existence of two equivalent binding sites (k = 14900 M-1) for the enzyme on each repeat unit of the thin filament. The Ca2+-sensitivity of this interaction reflects either a decrease in the strength of aldolase binding to these two sites (k = 8200 M-1) or the elimination of one site.
...
PMID:Binding of aldolase to actin-containing filaments. Quantitative reappraisal of the interactions. 730 56

The multicomponent solution, containing 15% of glycerol, 4.5% of proteins, 0.9% of sodium chloride, 0.33% of potassium chloride and water for injections, was proposed. The ferments activity (aminotransferases, cholinesterase, aldolase, alkaline phosphatase), blood coagulating system state (the prothrombin level, plasma tolerance, her recalcification time), the mineral elements contents (potassium, sodium, calcium), the contents of protein and its fractions in blood before and after an acute blood loss compensation with the multicomponent solution, and also its influence on the animals organism in prolonged daily (during 30 days) intravenous injection were studied. The combination of components in the solution permit to store the studying indexes on level close to initial; if the loss of blood compensates in the first hours, high survival of animals is insured. Negative reactions of organism while prolonged intravenous injection of the multicomponent solution are not revealed.
...
PMID:[Use of glycerin as a component of the solution in treating acute hemorrhage]. 760 2

To investigate whether the energy derived from glycolysis is functionally coupled to Ca2+ active transport in sarcoplasmic reticulum (SR), we determined whether glycolytic enzymes were associated with SR membranes and whether metabolism through these enzymes was capable of supporting 45Ca transport. Sealed right-side-out SR vesicles were isolated by step sucrose gradient from rabbit skeletal and cardiac muscle. Intravesicular 45Ca transport was measured after the addition of glycolytic substrates and cofactors specific for each of the glycolytic reactions being studied or after the addition of exogenous ATP and was expressed as transport sensitive to the specific Ca(2+)-ATPase inhibitor thapsigargin. We found that the entire chain of glycolytic enzymes from aldolase onward, including aldolase, GAPDH, phosphoglycerate kinase (PGK), phosphoglyceromutase, enolase, and pyruvate kinase (PK), was associated with SR vesicles from both cardiac and skeletal muscle. Iodoacetic acid, an inhibitor of GAPDH, eliminated 45Ca transport supported by fructose-1,6-diphosphate, the substrate for aldolase, but transport was completely restored by phosphoenolpyruvate (the substrate for PK), indicating that both of the ATP-producing glycolytic enzymes, GAPDH/PGK and PK, were associated with the SR and functionally capable of providing ATP for the Ca2+ pump. Addition of a soluble hexokinase ATP trap eliminated 45Ca transport fueled by exogenous ATP but had markedly less effect on 45Ca transport supported by endogenously produced ATP (via glycolysis). Similarly, at very low concentrations of ATP and ADP (10 to 50 nmol/L), ATP that was produced endogenously from ADP and phosphoenolpyruvate supported 15-fold more 45Ca transport than ATP that was supplied exogenously at the same concentration. These results are consistent with functional coupling of glycolytic ATP to Ca2+ transport and support the hypothesis that ATP generated by SR-associated glycolytic enzymes may play an important role in cellular Ca2+ homeostasis by driving the SR Ca2+ pump.
...
PMID:Functional coupling between glycolysis and sarcoplasmic reticulum Ca2+ transport. 778 86

Glycolytic enzymes are known to be controlled by reversible binding to cytoskeleton. Our previous experiments have shown that insulin, epidermal growth factor (EGF), and Ca2+ induce a rapid and transient stimulation of binding of glycolytic enzymes to muscle cytoskeleton. We show here that platelet-derived growth factor (PDGF) exerts a similar action. Incubation of rat diaphragm muscle in the presence of PDGF resulted in rapid and transient stimulation of binding of phosphofructokinase (EC 2.7.11) and aldolase (EC 4.1.2.13) to muscle cytoskeleton. The increase in cytoskeleton-bound glycolytic enzymes induced by PDGF was prevented by treatment with the calmodulin antagonists trifluoperazine or CGS 9343B (a potent and selective inhibitor of calmodulin activity), which strongly suggests that Ca(2+)-calmodulin is involved in this effect of PDGF. Similarly, we previously found that stimulation of cytoskeleton-bound glycolytic enzymes exerted by insulin, EGF, or Ca2+, was also calmodulin mediated. The present and previous results suggest that the rapid, Ca(2+)-calmodulin-mediated increase in cytoskeleton-bound glycolytic enzymes, may be a general mechanism in the cell, in signal transduction of insulin, growth factors, and other Ca(2+)-mobilizing hormones. The accelerated cytoskeletal glycolysis will provide local ATP, which is required for the rapid cytoskeletal-membrane rearrangements following binding of growth factor or hormone to its receptor.
...
PMID:Platelet-derived growth factor (PDGF) rapidly stimulates binding of glycolytic enzymes to muscle cytoskeleton, prevented by calmodulin antagonists. 785 79

We examined the kinetics study of serum enzyme after the administration of beta-blocking agents or alpha-stimulator in the experimental rats. Following the administration of beta-blocking agents, propranolol and pindolol, the serum levels of adenylate kinase, aldolase, lactate dehydrogenase and aspartate aminotransferase as well as that of creatine kinase increased in rats. The same was observed following the administration of noradrenaline (an alpha-stimulator). Isoenzyme pattern indicated that most of these enzymes were considered to be released from muscular tissues. There were also changes in serum calcium, inorganic phosphorus and magnesium, concurrently with the release of the enzymes into the serum.
...
PMID:Effects of beta-blocking agents on the release of various enzymes in muscular tissues. 796 81

We report here on a novel mechanism involved in epidermal growth factor (EGF) action, which shows that EGF rapidly stimulates binding of the glycolytic enzymes, phosphofructokinase (EC 2.7.1.11), and aldolase (EC 4.1.2.13) to muscle cytoskeleton. This effect was demonstrated both in vivo, in the tibialis anterior muscle from rats injected with EGF, and in vitro, in the isolated rat diaphragm muscle incubated with EGF. The increase in cytoskeleton-bound glycolytic enzymes induced by EGF was prevented, in both the in vivo and in vitro experiments, by treatment with the calmodulin antagonists trifluoperazine or CGS 9343B (a potent and selective inhibitor of calmodulin activity), which strongly suggests that Ca2+ and calmodulin are involved in this effect of EGF. Our previous findings have revealed that insulin or Ca2+ exert a similar rapid stimulation of cytoskeletal glycolysis, which is also calmodulin mediated. We now hypothesize that this may be a general mechanism of signal transduction in the cell, involving Ca(2+)-mobilizing hormones and growth factors, and supplying local ATP, in the vicinity of cytoskeleton-membrane, which is required for the rapid cytoskeletal-membrane rearrangements upon membrane-induced events.
...
PMID:Stimulatory effect of epidermal growth factor on binding of glycolytic enzymes to muscles cytoskeleton and the antagonistic action of calmodulin inhibitors. 837 34


<< Previous 1 2 3 4 5 6 7 8 Next >>

---