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)

As demonstrated previously, liver acini draining the blood from intraportally transplanted pancreatic islets in streptozotocin-diabetic rats are altered in various respects. The hepatocytes in these acini store glycogen and/or fat, and they show an increase in proliferation as well as in apoptotic activity. Thus, they are phenotypically similar to carcinogen-induced preneoplastic liver foci (glycogen-storing foci and sometimes also mixed cell foci). By means of catalytic enzyme histochemistry or immunohistochemistry, we investigated the activity of key enzymes of alternative pathways of carbohydrate metabolism and some additional marker enzymes (well known from studies on preneoplastic hepatic foci) in the altered liver acini surrounding the islet isografts. In addition, the expression of glucose transporter proteins 1 and 2 (GLUT-1 and GLUT-2) were investigated immunohistochemically. The activities of hexokinase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase, and glucose-6-phosphate dehydrogenase were increased, whereas the activities of glycogen phosphorylase, adenylate cyclase, glucose-6-phosphatase, and membrane-bound adenosine triphosphatase were decreased in the altered liver acini. The expression of GLUT-2 was also decreased. GLUT-1 and glutathione S-transferase placental form were not expressed, and the activities of glycogen synthase and gamma-glutamyl-transferase remained unchanged. All changes of the enzyme activities were in line with the well known effects of insulin and resembled alterations characteristic of preneoplastic liver foci observed in different models of hepatocarcinogenesis. It remains to be clarified in long-term experiments whether or not these foci represent preneoplastic lesions and may proceed to neoplasia.
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PMID:Altered liver acini induced in diabetic rats by portal vein islet isografts resemble preneoplastic hepatic foci in their enzymic pattern. 864 65

The direct effects of cadmium on the functions and metabolism of renal tubular epithelial cells were observed with radio-immune assay, cytochemical and biochemical methods to study further the mechanism of nephrotoxicity of cadmium. Results revealed uptake of alpha-methyl-D-glucoside (alpha-MG) in renal tubular epithelial cells obviously reduced, outflow of potassium ions increased, c-AMP content reduced and activity of Na+-K+-ATPase was inhibited significantly after exposure to cadmium. Electrochemical gradient of tubular cells maintained by Na+-K+-ATPase played an important role in transference of sodium and glucose, and damage in energy resource system within tubular epithelial cells may be one of the pathogenic mechanisms of kidney injury caused by cadmium. In addition, changes in a group of biological markers and functional enzymes (alkaline phosphatase, AKP; gamma-glutamyltransferase, gamma-GT; lactate dehydrogenase, LDH; glucose-6-phosphate dehydrogenase, G-6-PD; N-acetylglucoside, NAG) were determined in the study, and it was found that they all could reflect better the degree of injury in tubular epithelial cells and their metabolic status and could be used in clinical practice.
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PMID:[Toxicity of cadmium and its mechanism on renal tubular epithelial cells in vitro]. 875 54

By participating in glutathione (GSH) synthesis, gamma-glutamyl transpeptidase (GGT) influences the GSH redox cycle, which is a major contributor in protecting against reactive oxygen metabolites. This study determined the effect of prolonged exposure of neonatal rats to > 98% oxygen on expression of GGT and on GSH metabolism. Lungs of neonatal rats chronically exposed to hyperoxia had increased expression of GGT mRNA, resulting in significantly higher GGT protein levels and enzyme activity than in lungs of animals raised in room air. Hyperoxia also upregulated glucose-6-phosphate dehydrogenase, but Na-K-ATPase activity was not changed. GGT mRNA, protein level, and enzyme activity returned to control levels after recovery in room air for 3 days. Levels of GSH, glutathione disulfide, and protein-bound GSH (S-glutathiolated protein) rose with hyperoxia and fell during recovery. S-glutathiolation is likely a mechanism for protection and a regulatory modification of protein sulfhydryl groups. Hyperoxia-induced upregulation of GGT and the concomitant increase in protein S-glutathiolation appear to be additional components fundamental in protecting the lung against oxidative injury.
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PMID:Hyperoxia enhances expression of gamma-glutamyl transpeptidase and increases protein S-glutathiolation in rat lung. 877 34

In 63 children with severe meningococcal infection (MI) and meningitides of another origin red cell metabolism was studied: levels of ATP, ADP, AMP, ATP/ADP, ATP/AMP, energetic charge, 2,3-DPG, FAD, piruvate, lactate, activity of lactate dehydrogenase, piruvate kinase, glucose-6-phosphate dehydrogenase, glutatione reductase, Mg2+, Na+, K(+)-dependent ATPase. All the disease periods were characterized by combined pathobiochemical shifts of different degree typical for varying metabolic systems and correlating with the infection severity. The discussion covers pathogenetic and clinical significance of red cell metabolism shifts in patients with MI and purulent meningitides.
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PMID:[The dynamics of erythrocyte metabolism in severe forms of meningococcal infection and suppurative meningitis in children]. 904 77

The pregnant rats were treated with formaldehyde (0.5 mg/kg daily per os) during whole period of pregnancy. The activity of cytochrome-c-oxidase, malate dehydrogenase, nucleotidase, glucose-6-phosphatase, beta-glucuronidase, N-acetyl-beta-glucosaminidase, beta-galactosidase, H(+)-ATPase, glutamate dehydrogenase, NAD- and NADP-isocitrate dehydrogenase, fructose-bisphosphate aldolase, glucose-6-phosphate dehydrogenase and content of protein in liver celts of offsprings (newborns, 2 weeks age and 2 months age) were studied. It was shown differences in development enzyme systems of control and experimental animals during ontogenesis.
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PMID:[Experimental study of the effect of formaldehyde during embryogenesis on the activity of rat liver enzyme systems in ontogenesis]. 913 53

Zymomonas mobilis growing aerobically with 20 g glucose-1 (carbon-limited) in a chemostat exhibited an increase in both the molar growth yield (Yx/s) and the maximum molar growth yield (Yx/smax) and a decrease in both the specific substrate consumption rate (qs) and the maintenance energy consumption rate (me). Stepwise increase in the input oxygen partial pressure showed that anaerobic-to-aerobic transitional adaptation occurred in four stages: anaerobic (0 mm HgO2), oxygen-limited (7.6- 230 mm HgO2), intermediate (273 mm HgO2), and oxygen excess (290 mm HgO2). The steady-state biomass concentration, Yx/s, and intracellular ATP content increased between oxygen partial pressures of 7.6 and 120 mm HgO2, accompanied by a decrease in the qs and the specific acid production rate. The membrane ATPase activity decreased with increasing oxygen partial pressure and reached its lowest levels at 273 mm HgO2, which was the highest input oxygen partial pressure where steady-state conditions were possible. Glucokinase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and alcohol dehydrogenase activities also decreased when the oxygen partial pressure was increased above 15 mm Hg, whereas pyruvate decarboxylase was unaffected by aeration. Growth inhibition at 290 mm HgO2 was characterised by a drastic reduction in the pyruvate kinase activity and a collapse in the intracellular ATP pool. The growth and enzyme data suggest that at low glucose concentrations and oxygen-limited conditions, the increase in biomass yields is a reflection of a redirection of ATP usage rather than a net increase in energy production.
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PMID:Changes in the growth and enzyme level of Zymomonas mobilis under oxygen-limited conditions at low glucose concentration. 921 13

Baker's yeast cells accumulate osmolytes as a response to several stress conditions such as high-temperature and low-temperature shifts, dehydration, or osmotic stress. One of the major osmolytes that accumulates is trehalose, which plays an essential role affecting the survival of yeast at the time of stress. In this report, we show that trehalose efficiently protects the function and the structure of two yeast cytosolic enzymes against chemical denaturation by guanidinium chloride. Other sugars tested also protected yeast pyrophosphatase and glucose-6-phosphate dehydrogenase structure against guanidinium chloride effects, but were not as efficient at protecting enzyme activity. The thermostable pyrophosphatase from Bacillus stearothermophilus was also protected by several sugars against the chaotropic properties of guanidinium chloride, but was only protected by trehalose against functional inactivation. The function of the membrane-embedded H+-ATPase from yeast could not be protected by any of the tested sugars, although all of the sugars protected its structure from guanidinium-chloride-induced unfolding. The results presented in this study suggest that several sugars are able to prevent protein unfolding induced by a chaotropic compound. However, prevention of functional inactivation depends on the nature of the sugar. Trehalose was the most efficient, being able to protect many cytosolic enzymes against guanidinium chloride. The efficiency of protection also depended on the nature of the protein tested. This might explain why trehalose is one of the osmolytes accumulated in yeast and also why it is not the only osmolyte to accumulate.
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PMID:Carbohydrate protection of enzyme structure and function against guanidinium chloride treatment depends on the nature of carbohydrate and enzyme. 931 Mar 55

Rabbits given 1 ppm of vanadate in drinking water for twelve months showed (a) increased plasma levels of catecholamines (b) reduction of the arterial concentration of nitric oxide (c) lower activity of urine kallikrein and higher activities of urine kininases I and II and enkephalinase (d) reduced cardiac inotropism and augmented total peripheral resistance, with unchanged blood pressure levels (e) accumulation of the metal in the aorta and cardiac ventricles. Monoaminooxidase and glucose-6-phosphate dehydrogenase activities were increased by vanadate in both kidney and liver and that of NADH-diaphorase in the kidney, in which NADPH-diaphorase activity was reduced. Some of the above results were also obtained in rats given 10 and 40 ppm of vanadate in drinking water for six-seven months; these animals showed arterial hypertension and reduced activity of Na, K-ATPase in the kidney. Vanadium appears to act on the cardiovascular function through selective neurohumoral, autacoidal and transductional mechanisms only in part depending on the species.
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PMID:[Neurohumoral, autacoid and transductional mechanisms in the cardiovascular effects of vanadate: histochemical correlations]. 937 36

The article presents data of research concerning levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), activity of Na, K- and Ca, Mg-dependent adenosine triphosphatases, glucose-6-phosphate dehydrogenase, concentrations of sodium, potassium, calcium, magnesium and phosphorus in workers contacting some chemicals (pseudocumene, durene, dioxane-1,4, pyromellitic dianhydride, etc.) at work. All examinees were divided into 3 groups in consideration with intensity of chemical exposure: group 1--workers free of the exposure, group 2--workers exposed to the chemicals 2-3 times a week, group 3--workers exposed to the chemicals constantly at work during 3-5 years. Healthy individuals having no occupational exposure to the chemicals formed a reference group. Members of the groups 2 and 3 demonstrated lower levels of ATP, potassium, magnesium, calcium, decreased activity of Ca, Mg-dependent adenosinetriphosphatase and higher levels of ADP, AMP, Na, P and increased activity of Na, K-dependent adenosinetriphosphatase and glucose-6-phosphate dehydrogenase.
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PMID:[Changes in biochemical parameters of erythrocytes in workers engaged in pyromellitic dianhydride production]. 982 85

Polynucleotide phosphorylase (PNPase) is a prokaryotic enzyme that catalyzes phosphorolysis of polynucleotides with release of NDPs. It is also believed to play a key role in turnover of prokaryotic transcripts, thus regulating gene expression. At the moment, only radioisotopic methods are available for assaying PNPase in crude extracts; these involve incubating [32P]phosphate and poly(A) in the presence of the enzyme, separating [32P]phosphate from [32P]ADP, and quantifying ADP by scintillation counting. Photometric assay using pyruvate kinase and lactate dehydrogenase as auxiliary enzymes is not feasible in crude extracts because of endogenous ATPase activities, which regenerate ADP from the ATP released by pyruvate kinase. Here, we present a simple photometric assay that uses a cyclic detection system which, due to the sequential action of pyruvate kinase and hexokinase, results in an exponential increase of ADP and glucose 6-phosphate. Glucose 6-phosphate is then revealed by a glucose-6-phosphate dehydrogenase reaction. Based on the theoretical model, a linear increase in absorbance is predicted as a function of the square of the reaction time, with a slope proportional to PNPase activity. Experimental data confirmed the theoretical predictions and showed that the assay was quantitative and unquestionably specific. We also devised a simple procedure for determining absolute enzyme activities (expressed in micromoles of product formed per minute) using exact amounts of pure PNPase as internal standards.
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PMID:Photometric assay for polynucleotide phosphorylase. 1022 10


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