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)

The histochemical activities of myofibrillar adenosine triphosphatase (ATPase), succinic dehydrogenase (SDH) and alpha glycerophosphate dehydrogenase (alpha-GPD) were studied in intrafusal muscle fibres of rat fast and slow muscles. The ATPase reaction was carried out after the three standard acid preincubations. The cold K2-EDTA preincubated ATPase reaction product was similar to that seen following the regular or alkali-preincubated ATPase reaction, except that the intermediate bag fibres exhibited much higher activity after cold K2-EDTA preincubation. Following either acetic acid solution or cold and room temperature K2-EDTA-preincubation, followed by the ATPase reaction, chain fibres of the fast muscles vastus lateralis and extensor digitorum longus exhibited a very low amount of reaction product as compared with those of the slow soleus. Veronal acetate and K2-EDTA preincubations (and equally preincubation in acetic acid solution) resulted in acid stable ATPase activity along the entire length of the typical bag fibres but only in the polar regions of the intermediate bag fibres. On the basis of differing alpha-GPD reaction, two sub populations of nuclear chain fibres were discovered in one spindle. It is a matter of conjecture, to what extent the histochemical differences of intrafusal fibres from fast and slow muscles reflects functional distinctions in the response to stretch of muscle spindles from fast and slow muscles.
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PMID:A histoenzymatic study of rat intrafusal muscle fibres. 15 74

Folate nephropathy was selected as a model to study renal mitochondrial response after tubular injury. 20 h after injection, 14C-leucine incorporation was suppressed to 20--30% of control, 14C-mannose incorporation was 63--78% greater than control while the activities of succinic dehydrogenase and monoamine oxidase were unaltered. By 40 h, 14C-leucine incorporation had been restored to control values. Also, at 20 h, ATPase activity sensitive to oligomycin inhibition had increased by 45--73%, whereas K+-stimulated ATPase activity was reduced in the experimental mitochondrial fractions. The results are discussed along with other studies of mitochondria in experimental renal disease.
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PMID:Alterations of mitochondrial properties in folate nephropathy. 16 16

Triton X-100-insoluble residues from Micrococcus lysodeikticus membranes were analyzed by crossed immunoelectrophoresis after dispersal of the residues in sodium dodecyl sulfate (SDS). Conditions which produce no obvious distortion of the immunoprecipitate profile and which allow qualitative and quantitative analyses of the antigens present in the extracts are described. Two main antigens were detected; these were identified as succinate dehydrogenase (EC 1.3.99.1) and adenosine triphosphatase (EC 3.6.1.3). As determined by peak area estimations, the maximal release of succinate dehydrogenase and of adenosine triphosphatase from Triton X-100-insoluble membrane residues occurred at protein/SDS ratios of about 4.3:1 (0.2% SDS) and 6.8:1 (0.13% SDS), respectively. A comparison of enzyme activities of SDS extracts with those of untreated, control Triton X-100-insoluble membrane residues indicated that both the succinate dehydrogenase and the adenosine triphosphatase antigens were released with a full (or enhanced) catalytic potential at or below concentrations of SDS required to effect maximal solubilization of the enzyme in question. Evidence is also presented to suggest that the more acidic of the two components detected by crossed immunoelectrophoresis for the heterogeneous adenosine triphosphatase antigen is more sensitive to SDS than is the other. Both succinate dehydrogenase and adenosine triphosphatase lost catalytic activity and were denatured at protein/SDS ratios lower than 3.4:1.
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PMID:Immunochemical analysis of triton X-100-insoluble residues from Micrococcus lysodeikticus membranes. 16 Apr 15

The experiments were carried out on dogs. Experimental animals were subjected to the trauma of the thorax during operation. The localization and activity of succinic dehydrogenase, NADH2-tetrazole reductase, adenosine triphosphatase, alkaline and acid phosphates in the kidneys were examined. An increase of the activity of all the investigated enzymes takes place under the influence of the stress. On the basis of the investigations it can be supposed that the processes of oxygen phosphorylation and active transport are intensified. An increase of the activity of acid phosphates gives evidence of the intensity of phagocytosis and pinocytosis processes in the kidney.
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PMID:Histoenzymatic changes in the dog kidney in an experimentally induced crushing injury of the thorax. 16 20

The effect of temperature on the activation energies of mitochondrial enzymes of the yeast Saccharomyces cerevisiae was examined. Non-linear Arrhenius plots with discontinuities in the temperature range 14-19 degrees C and 19-22 degrees C were observed for the respiratory enzymes and mitochondrial ATPase (adenosine triphosphatase) respectively. A straight-line Arrhenius plot was observed for the matrix enzyme, malate dehydrogenase. The activation energies of the enzymes associated with succinate oxidation, namely, succinate oxidase, succinate dehydrogenase and succinate-cytochrome c oxidoreductase, were in the range 60-85kJ/mol above the transition temperature and 90-160kJ/mol below the transition temperature. In contrast, the corresponding enzymes associated with NADH oxidation showed significantly lower activation energies, 20-35kJ/mol above and 40-85kJ/mol below the transition temperature. The discontinuities in the Arrhenius plots were still observed after sonication, treatment with non-ionic detergents or freezing and thawing of the mitochondrial membranes. Discontinuities for cytochrome c oxidase activity were only observed in freshly isolated mitochondria, and no distinct breaks were observed after storage at -20 degrees C. Mitochondrial ATPase activity still showed discontinuities after sonication and freezing and thawing, but a linear plot was observed after treatment with non-ionic detergents. The results indicate that the various enzymes of the respiratory chain are located in a similar lipid macroenvironment within the mitochondrial membrane.
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PMID:Phase transitions in yeast mitochondrial membranes. The effect of temperature on the energies of activation of the respiratory enzymes of Saccharomyces cerevisiae. 16 75

Male Wistar rats were given 50 mug of aflatoxin B1 twice a week for 4 weeks, and thereafter 75 mug twice a week for 10 weeks. Their livers were investigated histologically and histochemically for glycogen, RNA, fat, alkaline and acid phosphatases, adenosine triphosphatase, 5'-nucleotidase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, succinic dehydrogenase, and alkaline and acid nucleases. No significant lesions occurred before 15 weeks. During this period, the liver was histochemically unchanged except for a periportal decrease of alkaline phosphatase and adenosine triphosphatase. Scattered hepatocytes with a strong glucose-6-phosphatase activity appeared. These changes represent toxic effects of aflatoxin B1 and are irrelevant to carcinogenesis. From 15 weeks onward, three types of liver cell hyperplastic foci and nodules developed. Histologically, and with respect to glycogen, fat, and RNA content, only two of these types were considered as potential precursors of hepatocarcinomas. However, all types exhibited a decrease or absence of the enzymes studied. Both histological and histochemical changes stressed the complex heterogeneity existing between and within hepatic foci and nodules. From 11 months on, hepatocarcinomas developed. The tumors disclosed similar histochemical changes. This similarity further supports the "precarcinomatous" nature of hyperplastic foci and nodules. It appears that focal changes in surface as well as in cytoplasmic and nuclear enzymes are intimately and very early linked to the carcinogenic process. Whether they are fundamental or only represent an epiphenomenon remains unclear.
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PMID:Sequential histological and histochemical study of the rat liver during aflatoxin B1-induced carcinogenesis. 16 70

1. Functional properties of the ATPase complex are investigated in megamitochondria isolated from livers of weanling mice fed a diet containing 2% chloramphenicol, as an inhibitor of mitochondrial protein synthesis. 2. Whereas the specific activity of ATPase remains unchanged in chloramphenicol-induced megamitochondria, about 40% of the enyzme activity is resistant to inhibition by oligomycin, triethyltin or venturicidin. It is concluded that the ATPase complex lacks one or more components whose synthesis or accumulation is dependent on mitochondrial translation. The inhibitor-resistant ATPase portion appears tightly bound to the mitochondrial membrane. 3. Respiratory chain phosphorylation is tightly coupled in isolated megamitochondria. ATP synthesis and ATP-Pi exchange are diminished by 40%, as compared to control mitochondria, but both processes are sensitive to oligomycin, triethyltin or venturicidin. 4. The decrease in ATP synthesis and ATP-Pi exchange in megamitochondria correlates quite well with the emergence of inhibitor-resistant ATPase. 5. The following electron transport activities in the megmitochondria are reduced: NADH-cytochrome c reductase, by 60%, cytochrome oxidase, by 80%; the amount of antimycin required to gain complete inhibition of the bc1-segment is diminished by more than 50%. On the other hand succinate dehydrogenase activity is increased by 50%. 6. Chloramphenicol-induced megamitochondria appear to be a useful system for studying the role of mitochondrial translation in the assembly of mammalian mitochondria.
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PMID:ATPase complex and oxidative phosphorylation in chloramphenicol-induced megamitochondria from mouse liver. 17 30

Plasma membranes were isolated from rat liver mainly under isotonic conditions. As marker enzymes for the plasma membrane, 5'-nucleotidase and (Na+ + K+)-ATPase were used. The yield of plasma membrane was 0.6-0.9 mg protein per g wet weight of liver. The recovery of 5'-nucleotidase and (Na+ +K+)-ATPase activity was 18 and 48% of the total activity of the whole-liver homogenate, respectively. Judged from the activity of glucose-6-phosphatase and succinate dehydrogenase in the plasma membrane, and from the electron microscopic observation of it, the contamination by microsomes and mitochondria was very low. A further homogenization of the plasma membrane yielded two fractions, the light and heavy fractions, in a discontinuous sucrose gradient centrifugation. The light fraction showed higher specific activities of 5'-nucleotidase, alkaline phosphatase, (Na+ +K+)-ATPase and Mg2+-ATPase, whereas the heavy one showed a higher specific activity of adenylate cyclase. Ligation of the bile duct for 48 h decreased the specific activities of (Na2+ +K+)-ATPase and Mg2+-ATPase in the light fraction, whereas it had no significant influence on the activities of these enzymes in the heavy fraction. The specific activity of alkaline phosphate was elevated in both fractions by the obstruction of the bile flow. Electron microscopy on sections of the plasma membrane subfractions showed that the light fraction consisted of vesicles of various sizes and that the heavy fractions contained membrane sheets and paired membrane strips connected by junctional complexes, as well as vesicles. The origin of these two fractions is discussed and it is suggested that the light fraction was derived from the bile front of the liver cell surface and the heavy one contained the blood front and the lateral surface of it.
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PMID:Subfractionation of rat liver plasma membrane. Uneven distribution of plasma membrane-bound enzymes on the liver cell surface. 17 48

Temperature-responsive microsomes of the ciliate protozoan Tetrahymena have been originally fractionated by step centrifugation on two-layered, Mg2+-containing sucrose gradients. Three fractions have been obtained, which are termed smooth I, smooth II and rough according to the appearance of the membrane vesicles upon electron-microscopy. Smooth I, smooth II, and rough microsomes exhibit RNA/protein ratios of 0.09, 0.20, and 0.34; their phospholipid/protein ratios and their neutral lipid/phospholipid ratios were 0.52, 0.43 and 0.25, and 0.17, 0.18 and 0.13, respectively. All three fractions contain equivalent, low succinic dehydrogenase and 5'-nucleotidase activities. Glucose-6-phosphatase and acid phosphatase are more concentrated in smooth I membranes than in rough membranes. The reverse is true for ATPase. The smooth II membranes occupy an intermediate position except that their ATPase activity is the lowest of the three fractions. The specific activities of these enzymes of the three microsomal fractions are compared to those of homogenates of whole cells. Thin-layer chromatography reveals a very similar polar and nonpolar lipid pattern of the three microsomal fractions. The major phospholipid compounds are phosphatidlethanolamine, glycerideaminoethylphosphonate and phosphatidylcholine, while diglycerides, an unknown NL-compound, and triglycerides are the major apolar lipids. Gas liquid chromatography shows that the fatty acids are mainly even-numbered ranging between C12 and C18. The smooth I, smooth II and rough membranes contain 65.2, 69.3 and 72.7% unsaturated fatty acids in their polar lipids, whereas only 52.7, 49.7 and 48.3% unsaturated acids are found in their apolar lipids, respectively. The fatty acids are more unevenly distributed among the individual polar lipids than in the apolar ones.
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PMID:Membranes of Tetrahymena. IV. Isolation and characterization of temperature-responsive smooth and rough microsomal subfractions. 17 62

1. Incubation of human and rat hepatoma cells with insulin (1 mU/10(6) cells) decreases their content of adenosine 3':5'-monophosphate by more than half after 1 h and by about a quarter after 4 h. 2. The activities of the ATP-metabolising enzymes, adenylate kinase and Mg2+-adenosine triphosphatase are significantly increased by insulin within 1 h and after 4 h. Activity of succinate dehydrogenase and lactic dehydrogenase showed no change at either time interval. 3. Insulin markedly stimulated glucose 6-phosphate dehydrogenase activity within 1 h but by 4 h the increase was less apparent. Glutamate dehydrogenase activity by contrast was not increased by 1 h but was elevated at 4 h.
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PMID:The influence of insulin on various enzyme activities in human and rat hepatoma cells. 17 8


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