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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When 10(-6) M oubain is added to human red cell that have been incubated without glucose for two hours, there is a significant shift in the 31P nuclear magnetic resonances of both phosphate groups of cellular 2,3-diphosphoglycerate, which is not found in control cells incubated with glucose. This means that an effect induced by ouabain on the outside of the red cell membrane is transmitted through the membrane to alter the environment of an intracellular metabolite. Experiments with glycolytic cycle inhibitors have indicated that the intracellular ligand responsible for the resonance shifts is monophosphoglycerate mutase which requires 2,3-diphosphoglycerate as a cofactor for the reaction it catalyzes. To account for this finding a hypothesis is presented that the (Na+ + K+)-ATPase in human red cells is linked to monophosphoglycerate mutase through the agency of phosphoglycerate kinase. Evidence is presented for the existence of phosphoglycerate kinase/monophosphoglycerate mutase in solution. It is shown that this complex can interact with the cytoplasmic face of (Na+ + K+)-ATPase at the outside surface of inside out red cell vesicles, and that this interaction is inhibited when 10(-6) M ouabain is contained within the vesicle. Neither monophosphoglycerate mutase nor phosphoglycerate kinase is significantly bound to the inside surface of the intact human red cell, but glyceraldehyde 3-phosphate dehydrogenase is; it is shown that this enzyme also interacts with the cytoplasmic face of the (Na+ + K+)-ATPase and that the interaction is inhibited by 10(-6) M ouabain.
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PMID:Membrane mediated link between ion transport and metabolism in human red cells. 83 95

The storage lesion which limits the shelf life of human blood in blood banking is associated with a metabolic loss of 2,3-diphosphoglycerate and ATP. This metabolic loss is driven by intracellular ATPase which are usually considered to include the ion pumps and the reactions which maintain the discoid shape of the human erythrocyte. Under the acidic conditions of blood storage, the energy-yielding reactions of the glycolytic pathway are restricted at the hexokinase and phosphofructokinase steps. We show here that under such circumstances the enzyme of the diphosphoglycerate shunt, diphosphoglycerate mutase/phosphatase and the glycolytic enzyme phosphoglycerate kinase can form a futile cycle with ATPase activity. This ATPase activity responds to 2-phosphoglycolate which is known to activate both diphosphoglycerate mutase and diphosphoglycerate phosphatase reactions. When the enzymes of the futile cycle are combined with the enzymes of the lower glycolytic pathway in a reconstitution experiment designed to represent conditions within the stored erythrocyte, the futile cycle does provide an ATPase activity which results in the metabolic loss of 2,3-diphosphoglycerate. An isotope incorporation experiment demonstrates that the futile cycle is active in glucose-depleted erythrocytes.
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PMID:A futile cycle in erythrocyte glycolysis. 406 53

1. Intracellular concentrations of intermediates and cofactors of glycolysis were measured in guinea-pig cerebral cortex slices incubated under varying conditions. 2. Comparison of mass-action ratios with apparent equilibrium constants for the reactions of glycolysis showed that hexokinase, phosphofructokinase and pyruvate kinase catalyse reactions generally far from equilibrium, whereas phosphoglucose isomerase, aldolase, phosphoglycerate kinase, phosphoglycerate mutase, enolase, adenlyate kinase and creatine phosphokinase are generally close to equilibrium. The possibility that glyceraldehyde 3-phosphate dehydrogenase may catalyse a ;non-equilibrium' reaction is discussed. 3. Correlation of changes in concentrations of substrates for enzymes catalysing ;non-equilibrium' reactions with changes in rates of glycolysis caused by alteration of the conditions of incubation showed that hexokinase, phosphofructokinase, pyruvate kinase and possibly glyceraldehyde 3-phosphate dehydrogenase are subject to metabolic control in cerebral cortex slices. 4. It is suggested that the glycolysis is controlled by two regulatory systems, the hexokinase-phosphofructokinase system and the glyceraldehyde 3-phosphate dehydrogenase-pyruvate kinase system. These are discussed. 5. It is concluded that the rate of glycolysis in guinea-pig cerebral cortex slices is limited either by the rate of glucose entry into the slices or by the hexokinase-phosphofructokinase system. 6. It is concluded that addition of 0.1mm-ouabain to guinea-pig cerebral cortex slices causes inhibition of either glyceraldehyde 3-phosphate dehydrogenase or phosphoglycerate kinase or both, in a manner independent of the known action of ouabain on the sodium- and potassium-activated adenosine triphosphatase.
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PMID:Control of glycolysis in cerebral cortex slices. 422 84

1. The action of beryllium on the following enzymes has been examined: alkaline phosphatase (Escherichia coli and kidney), acid phosphatase, phosphoprotein phosphatase, apyrase (potato), adenosine triphosphatase (liver nuclei, liver mitochondria, brain microsomes), glucose 6-phosphatase, polysaccharide phosphorylases a and b, phosphoglucomutase, hexokinase, phosphoglyceromutase, ribonuclease, A-esterase (rabbit serum), cholinesterase (horse serum), chymotrypsin. Alkaline phosphatase and phosphoglucomutase are inhibited by 1mum-beryllium sulphate whereas the other enzymes are largely unaffected by 1mm-beryllium sulphate. 2. Possible mechanisms for the inhibition of phosphoglucomutase and alkaline phosphatase are discussed.
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PMID:The inhibition of enzymes by beryllium. 428 87

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.
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PMID:Functional coupling between glycolysis and sarcoplasmic reticulum Ca2+ transport. 778 86

A patient with muscle phosphoglycerate mutase deficiency (PGAMD) and exercise-induced muscle cramps had tubular aggregates in muscle and increased muscle Ca2+-adenosine triphosphatase and calcium content. Two ischemic forearm exercise tests induced contractures in the patient. On dantrolene treatment, the patient became asymptomatic, and the ischemic test was performed without contracture. These findings suggest that cramps in muscle PGAMD are caused by a high calcium release from the sarcoplasmic reticulum relative to calcium re-uptake capacity.
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PMID:Muscle phosphoglycerate mutase deficiency with tubular aggregates: effect of dantrolene. 1044 98

To elucidate the molecular basis of muscle atrophy, we have performed the serial analysis of gene expression (SAGE) method with control and immobilized muscles of 10 rats. The genes that expressed >0.5% in muscle are involved in the following three functions: 1) contraction (troponin I, C and T; myosin light chain 1-3; actin; tropomyosin; and parvalbumin), 2) energy metabolism (cytochrome c oxidase I and III, creatine kinase, glyceraldehyde-3-phosphate-dehydrogenase, phosphoglycerate mutase, ATPase 6, and aldolase A), and 3) housekeeping (lens epithelial protein). Muscle atrophy appears to be caused by changes in mRNA levels of specific regulators of proteolysis, protein synthesis, and contractile apparatus assembling, such as polyubiquitin, elongation factor 2, and nebulin. Immobilization has produced a decrease more than threefold in gene expression of enzymes involved in energy metabolism, especially ATPase, cytochrome c oxidase, NADH dehydrogenase, and protein phosphatase 1. Differential gene expressions of selenoprotein W and uroporphyrinogen decarboxylase, which can be involved in oxidative stress, were also observed. Other genes with various functions, such as cholesterol metabolism and growth factors, were also differentially expressed. Moreover, novel genes regulated by immobilization were discovered. Thus, the current study allows a better understanding of global muscle characteristics and the molecular mechanisms of sedentarity and sarcopenia.
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PMID:Characterization of control and immobilized skeletal muscle: an overview from genetic engineering. 1125 86

Microbial proliferation and biofilm formation on biologic or inert substrates are characteristics of invasive Staphylococcus aureus infections and is associated with phenotypic alterations such as reduced antimicrobial susceptibility. To identify genes which are typically expressed in biofilms, a micro-representational-difference analysis (micro-RDA) was adapted for gram-positive bacteria and used with cDNA derived from populations of S. aureus DSM 20231 growing in a biofilm or plankonically. In comparison to previously described cDNA RDA protocols, micro-RDA has the advantages that only minimal quantities of total RNA are needed and, most importantly, that total RNA can be used since the large amount of rRNA in total RNA does not interfere with the micro-RDA procedure. Using a series of spiked controls with various amounts of MS2 RNA in a background of total RNA from S. aureus, the equivalent of five copies of MS2 per cell were detectable after three rounds of subtractive enrichment. Five genes were identified as being differentially expressed in biofilm versus planktonic cultures. These genes revealed homology to a threonyl-tRNA synthetase, a phosphoglycerate mutase, a triosephosphate isomerase, an alcohol dehydrogenase I, and a ClpC ATPase. Differential levels of expression were subsequently confirmed by standard Northern blotting. In conclusion, micro-RDA is a sensitive and specific method to detect transcripts differentially expressed as a function of different S. aureus growth conditions.
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PMID:Detection of differential gene expression in biofilm-forming versus planktonic populations of Staphylococcus aureus using micro-representational-difference analysis. 1142 8

Phosphoglucomutases catalyze the interconversion of D-glucose 1-phosphate and D-glucose 6-phosphate, a reaction central to energy metabolism in all cells and to the synthesis of cell wall polysaccharides in bacterial cells. Two classes of phosphoglucomutases (alpha-PGM and beta-PGM) are distinguished on the basis of their specificity for alpha- and beta-glucose-1-phosphate. beta-PGM is a member of the haloacid dehalogenase (HAD) superfamily, which includes the sarcoplasmic Ca(2+)-ATPase, phosphomannomutase, and phosphoserine phosphatase. beta-PGM is unusual among family members in that the common phosphoenzyme intermediate exists as a stable ground-state complex in this enzyme. Herein we report, for the first time, the three-dimensional structure of a beta-PGM and the first view of the true phosphoenzyme intermediate in the HAD superfamily. The crystal structure of the Mg(II) complex of phosphorylated beta-phosphoglucomutase (beta-PGM) from Lactococcus lactis has been determined to 2.3 A resolution by multiwavelength anomalous diffraction (MAD) phasing on selenomethionine, and refined to an R(cryst) = 0.24 and R(free) = 0.28. The active site of beta-PGM is located between the core and the cap domain and is freely solvent accessible. The residues within a 6 A radius of the phosphorylated Asp8 include Asp10, Thr16, Ser114, Lys145, Glu169, and Asp170. The cofactor Mg(2+) is liganded with octahedral coordination geometry by the carboxylate side chains of Asp8, Glu169, Asp170, and the backbone carbonyl oxygen of Asp10 along with one oxygen from the Asp8-phosphoryl group and one water ligand. The phosphate group of the phosphoaspartyl residue, Asp8, interacts with the side chains of Ser114 and Lys145. The absence of a base residue near the aspartyl phosphate group accounts for the persistence of the phosphorylated enzyme under physiological conditions. Substrate docking shows that glucose-6-P can bind to the active site of phosphorylated beta-PGM in such a way as to position the C(1)OH near the phosphoryl group of the phosphorylated Asp8 and the C(6) phosphoryl group near the carboxylate group of Asp10. This result suggests a novel two-base mechanism for phosphoryl group transfer in a phosphorylated sugar.
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PMID:Caught in the act: the structure of phosphorylated beta-phosphoglucomutase from Lactococcus lactis. 1208 83

The effect of glucocorticoid treatment on protein expression in bovine neutrophils was examined with a proteomic approach to address the mechanisms by which stress alters neutrophil function and predisposes to bacterial pneumonia in cattle. Calves 6 to 8 mo old were treated with dexamethasone (0.1 mg/kg), neutrophils were isolated 24 h later, and whole-cell lysates were examined by 2-dimensional electrophoresis. Differentially expressed protein spots were identified by peptide mass fingerprinting. The antimicrobial protein lactotransferrin was detected at increased amounts in the neutrophils of the dexamethasone-treated calves. Proteins detected at reduced amounts in the neutrophils of the dexamethasone-treated calves included annexin 1, phosphoglycerate mutase, Na(+) - K+ ATPase, and cathelicidin 1. These findings identify glucocorticoid-induced changes in the levels of neutrophil proteins involved in host defense, inflammation, and cellular metabolism and suggest additional mechanisms by which glucocorticoids affect neutrophil function.
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PMID:Altered protein expression in neutrophils of calves treated with dexamethasone. 1850 88


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