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:1.6.5.3 (complex I)
8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antigenic architecture of membrane vesicles prepared from Escherichia coli ML 308--225 has been studied using crossed immunoelectrophoresis. Progressive immunoadsorption experiments conducted with control vesicles and with physically disrupted vesicles were used to monitor and quantitate the expression of 14 different immunogens. Eleven immunogens, including NADH dehydrogenase (EC 1.6.33.3), D-lactate dehydrogenase (EC 1.1.1.27), dihydro-orotate dehydrogenase (EC 1.3.3.1), 6-phosphogluconate dehydrogenase (EC 1.1.1.43), polynucleotide phosphorylase (EC 2.3.7.8), and beta-galactosidase (EC 3.2.1.23), exhibit minimal expression (10% or less) unless the vesicles are disrupted. Three unidentified antigens are expressed to a similar extent in untreated and disrupted vesicles. Consideration of these and other results [Owen, P., & Kaback, H. R. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 3148] in terms of membrane polarity, dislocation of antigens, and possible transmembrane orientation of some immunogens reveals that over 95% of the membrane in the vesicle preparations is in the form of sealed sacculi with the same orientation as the intact cell. Furthermore, antigens are distributed across the membrane in a highly asymmetric manner, indicating that dislocation of components from the inner to the outer surface of the membrane during vesicle preparation does not occur to an extent exceeding 10%.
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PMID:Antigenic architecture of membrane vesicles from Escherichia coli. 21 21

Treating bovine epididymal spermatozoa with rutamycin or rotenone inhibited both respiration and motility supported by endogenous substrates. When oxidative phosphorylation had been blocked with various inhibitors, pyruvate was metabolized to yield ATP and restored motility. Fructose, which is metabolized via glycolysis to yield ATP, was also able to resuscitate the cells. Other substrates tested (lactate, acetate, alpha-ketoglutarate, or glyoxylate) were unable to restore motility in rutamycin-treated cells. In the presence of pyruvate, the phosphorylation uncoupler, carbonylcyanide-p-trifluoromethyoxphenylhydrazone, reduced motility and ATP to common levels in untreated cells or cells treated with rutamycin or rotenone. Pyruvate is thus metabolized to produce ATP by a pathway independent of oxidative phosphorylation associated with the electron transport chain. 5-Methoxyindole-2-carboxylic acid, an inhibitor of lipoyldehydrogenase, prevented the increase of motility and ATP in rutamycin-treated cells, indicating that alpha-keto acid oxidation is involved in the production of ATP from pyruvate when rutamycin is present. With pyruvate present, bongkrekic acid, antimycin A, and anaerobiosis eliminated motility, reduced ATP to low levels, and also significantly reduced the rate of pyruvate metabolism. Acetate was produced from pyruvate only when cellular ATP concentrations were low. Decreases in free carnitine concentrations showed that pyruvate initially used was converted to acetylcarnitine. The results indicate that the intramitochondrial lactate dehydrogenase X, which is unique to spermatozoa, allows the NADH resulting from pyruvate oxidation to reduce other pyruvate molecules to lactate. Pyruvate thus competes with, and can substitute for, the NADH dehydrogenase of the electron transport chain. Pyruvate rapidly repletes the acetylcarnitine pool under a variety of conditions.
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PMID:Pyruvate metabolism in bovine epididymal spermatozoa. 83 18

Cytophotometric measurements of the activities of 5 enzymes (succinate, malate, and NAD+-linked isocitrate dehydrogenases from the tricarboxylic cycle, lactate dehydrogenase from the Embden-Meyerhof pathway, and NADH dehydrogenase) were correlated with cell volume for neurones in the anterior horn of rabbit lumbar and cervical spinal cord. The data for succinate and isocitrate dehydrogenases indicated that these enzymes were at higher concentrations in the smaller neurones, which consist largely of interneurones. No preferential localization to particular sizes of cell could be assigned to the other enzymes studied. The relationship between enzyme distribution patterns and their possible role in contributing toward susceptibility to ischaemia of particular sizes of neurones is discussed.
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PMID:Quantitative oxidative enzyme histochemistry of the spinal cord. Part 2. Relation of cell size and enzyme activity to vulnerability to ischaemia. 117 87

In the subcommissural organ (SCO) of the guinea pig, rat, golden hamster, and mouse the activity and distribution of enzymes related to the energy-supplying metabolism and of some marker enzymes of different cell organelles have been investigated by means of mostly modified histochemical methods. The results were compared with findings in the ciliated ependyma of the ventricular wall and with those in the ependyma of the choroid plexus of the third ventricle. In the ependymal part of the SCO only a moderate activity of hexokinase is observed in its specialized columnar cells whereas a high activity is present both in the ciliated ependyma and the choroid plexus. - The staining pattern of glucose-6-phosphatase is similar to that of hexokinase but this enzyme is found is the SCO only. - Likewise hexokinase, glycogen granules and enzymes related to glycogen metabolism (phosphoglucomutase, uridine-diphosphoglucose pyrophosphorylase, glycogen synthetase and phosphorylase) are regularly found most numerous and active in the nuclear and supra-nuclear area of the ependymal part. These enzymes are less active in both the other ependymal regions. - Uridine-diphosphoglucose dehydrogenase could not be demonstrated in the SCO. The NADP-linked enzymes of the pentose phosphate shunt, glucose-6-phosphate and 6-phosphogluconate dehydrogenase, show a moderate activity which decreases also from the nuclear towards the apical area of the ependymal cells of the SCO. Enzymes of the glycolytic pathway, such as glucosephosphate isomerase, fructose-6-phosphate kinase, fructose-I,6-diphosphate aldolase, glyceraldehyde-3-phosphate and lactate dehydrogenase, are highly active in the SCO and are located mainly in the supranuclear area, too. Fructose-1,6-diphosphatase could not be demonstrated thus indicating that in the SCO the pathway is most probably only glycolytic but not gluconeogenetic. Compared to the ependyma of the ventricular wall and of the choroid plexus, in the SCO the M type subunits of lactate dehydrogenase predominate. Glycolytic enzymes are also very active in the choroid plexus but less in the ciliated ependyma. Compared to the ciliated ependyma and especially to the ependyma of the choroid plexus, the activities of enzymes which are only present in mitochondria (NAD-linked isocitrate dehydrogenase, succinate dehydrogenase, NAD-linked malate dehydrogenase after preextraction, cytochrome oxidase, 3-hydroxybutyrate and glycerolphosphate and glutamate dehydrogenase) are relatively low. Mitochondria are accumulated near the superior pole of the nuclei as well as in the most apical part of the ependymal cells. - The staining pattern of NADP-linked isocitrate and malate dehydrogenase as well as of NADH dehydrogenase suggests that these enzymes are localized both in and out of mitochondria. The extramitochondrial activity of the first two enzymes might be localized in the cytosol. The extramitochondrial activity of NADH dehydrogenase might be localized in the endoplasmic reticulum...
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PMID:Enzymatic organization of the subcommissural organ. 123 49

The triarylmethane derivative Victoria Blue-BO (VB-BO) and the chalcogenapyrylium (CP) dyes have potential for use in photochemotherapy, because they are taken up by the mitochondria of malignant cells and cause cell death. To clarify the mechanism of cell killing we examined the phototoxic effects of VB-BO and a series of three CP dyes on bioenergetic function in isolated rat liver mitochondria. Without photoirradiation, and irrespective of the respiratory substrate used, each of the compounds tested induced some uncoupling of oxidative phosphorylation. Visible irradiation of VB-BO produced an inhibition of mitochondrial respiration when glutamate plus malate, but not succinate, was used as the respiratory substrate. With photoirradiation VB-BO was also shown to inhibit rotenone-sensitive NADH-cytochrome c reductase activity, but it had no effect on succinate-cytochrome c reductase activity. These data indicate that photoactivation of VB-BO produces selective inhibition of mitochondrial respiratory complex I. Photoirradiation of the CP dyes inhibited both complex I and complex II initiated respiratory activity. With photoirradiation, the CP dyes also inhibited both NADH- and succinate-cytochrome c reductase activities, as well as other membrane-bound enzymes, cytochrome c oxidase and succinate dehydrogenase, but not the mitochondrial matrix enzyme, citrate synthetase, or the cytosolic enzyme, lactate dehydrogenase. alpha-Tocopherol protected bioenergetic activities against CP dye photodamage. These results suggest that mitochondrial photosensitization by CP compounds is mediated by the production of membrane-damaging singlet oxygen which causes nonspecific damage to membranes and membrane-bound enzymes.
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PMID:Mitochondrial toxicity of cationic photosensitizers for photochemotherapy. 217 36

Growth of Mycobacterium phlei under low oxygen tension resulted in specific activities two to twenty times lower for formate dehydrogenase, malate dehydrogenase, beta-hydroxybutyrate dehydrogenase, lactate oxidase and NADH dehydrogenase than when cultures were grown under high aeration. An increase in fumarate reductase and succinate dehydrogenase occurred with M. phlei grown under low oxygen tension. Malate: vitamin K dehydrogenase and glucose-6-phosphate dehydrogenase activity were not significantly affected by the oxygen tension used to grow the bacteria, and neither culture contained a lactate dehydrogenase. With growth of M. phlei in conditions of low oxygen tension, cytochrome a was not detected, but cytochrome b was prominent in membranes and cytochrome c was present in the soluble fraction.
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PMID:Influence of oxygen tension on the respiratory activity of Mycobacterium phlei. 318 14

A rapid decrease in male fertility in laboratory animals exposed to 1,2-dibromo-3-chloropropane (DBCP) has been suggested to be due, in part, to a postglycolytic inhibition of sperm carbohydrate metabolism. The present studies were performed to identify the specific site of DBCP-induced inhibition of intermediary metabolism. 14CO2 generation by epididymal sperm, isolated from Fischer 344 rats, was measured using radiolabeled tricarboxylic acid (TCA) cycle intermediates: acetyl CoA, citrate, alpha-ketoglutarate, and succinate. There was 0-28% inhibition of CO2 generation after addition of 0.5 mM DBCP and 81-98% inhibition with 3 mM DBCP, with all four substrates. The activities of alpha-ketoglutarate dehydrogenase, pyruvate dehydrogenase, malate dehydrogenase, and lactate dehydrogenase were not inhibited by DBCP. Since the DBCP-induced inhibition of metabolism of different substrates to CO2 was similar, and since DBCP did not inhibit enzyme activities of glycolysis or the TCA cycle, a common site of inhibition was suspected. In evaluations of mitochondrial electron transport chain activity, DBCP (3 mM) inhibited oxygen consumption resulting from metabolism of endogenous substrates plus alpha-ketoglutarate or malate by about 80%. When succinate, an FAD-dependent oxidation, was used as a substrate, oxygen consumption was not inhibited by DBCP. It is concluded that DBCP inhibits sperm carbohydrate metabolism at the NADH dehydrogenase step in the mitochondrial electron transport chain.
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PMID:A biochemical basis for 1,2-dibromo-3-chloropropane-induced male infertility: inhibition of sperm mitochondrial electron transport activity. 367 26

1. The reconstitution of oxidase activity in cell-free extracts of a mutant of Escherichia coli K12Ymel, that require 5-aminolaevulinic acid for growth on non-fermentable carbon sources, is described. 2. The reconstitution is dependent on haematin or a haem extract from a prototrophic strain of E. coli, and the product of the reaction has been identified as NADH-reducible cytochrome b. 3. The requirement for haematin cannot be replaced by four other porphyrins. Coproporphyrin III does not inhibit the haematin-dependent reconstitution, mesoporphyrin IX and protoporphyrin IX apparently compete with haematin for a binding site on the cytochrome apoprotein(s) and deuteroporphyrin IX binds to cytochrome apoprotein(s) and cannot be subsequently replaced by haematin. 4. The properties of electron-transport particles from cell-free extracts of the mutant strain, grown aerobically in the presence or absence of 5-aminolaevulinic acid, are described. In the absence of 5-aminolaevulinic acid no detectable cytochromes are produced, and oxidase activities are lowered but there is no apparent effect on the activities of the NADH dehydrogenase and d-lactate dehydrogenase. 5. The reconstitution of oxidase activity by electron-transport particles from cells grown in the absence of 5-aminolaevulinic acid requires ATP and haematin, and the product of the reaction was identified as NADH-reducible cytochrome b. 6. It is concluded that the cytochrome apoproteins are synthesized and incorporated into the cytoplasmic membrane of E. coli in the absence of haem synthesis. The subsequent reconstitution of functional cytochrome(s) requires protohaem, but the nature of the side chain on the 2 and 4 positions of the porphyrin appears to be important.
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PMID:The reconstitution of oxidase activity in membranes derived from a 5-aminolaevulinic acid-requiring mutant of Escherichia coli. 415 Jun 52

The effects of an oral neomycin and penicillin regimen on intestinal bacteriology and on morphology and function of the small intestine of mice were investigated. Quantitative and qualitative stool cultures on selective media of the treated animals revealed only growth of yeast organisms. The treated animals developed enlargement of the ceca with fluid contents and watery stools, resembling characteristics of germfree animals. Radioautography with tritiated thymidine revealed an increased epithelial cell migration rate in the mice treated with the antibiotics for 3 to 5 wk. A slight increase in villus height was also noted. The treated male mice showed greater variance than the treated females in epithelial cell migration rates. Histochemical staining reactions showed a decrease in nonspecific esterase and in NADH dehydrogenase activity in the proximal gut of the antibiotic animals. Stains of distal gut and those for acid and alkaline phosphatase, NADPH dehydrogenase, lactic dehydrogenase, and succinic dehydrogenase were similar to the controls. A slight increase in sucrase activity and a slight decrease in lactase activity in the antibiotic animals was observed in contrast to control animals. Germfree mice, however, had greater sucrase and lactase activity. Transport of L-methionine was slightly reduced in the distal segment of the treated animals. Since the direction of these changes is away from the intestinal state observed in germfree animals, they are probably the result of the direct action of the antibiotics on the gut.
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PMID:Effects of neomycin and penicillin administration on mucosal proliferation of the mouse small intestine. With morphological and functional correlations. 438 18

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
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PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7


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