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:1.1.1.37 (malate dehydrogenase)
4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cell-free extract supernatant fluids of Pseudomonas aeruginosa were shown to lack malic dehydrogenase but possess a nicotinamide adenine dinucleotide (NAD)- or NAD phosphate (NADP)-dependent enzymatic activity, with properties suggesting a malic enzyme (malate + NAD (NADP) --> pyruvate + reduced NAD (NADH) (reduced NADP [NADPH] + CO(2)), in agreement with earlier findings. This was confirmed by determining the nature and stoichiometry of the reaction products. Differences in heat stability and partial purification of these activities demonstrated the existence of two malic enzymes, one specific for NAD and the other for NADP. Both enzymes require bivalent metal cations for activity, Mn(2+) being more effective than Mg(2+). The NADP-dependent enzyme is activated by K(+) and low concentrations of NH(4) (+). Both reactions are reversible, as shown by incubation with pyruvate, CO(2), NADH, or NADPH and Mn(2+). The molecular weights of the enzymes were estimated by gel filtration (270,000 for the NAD enzyme and 68,000 for the NADP enzyme) and by sucrose density gradient centrifugation (about 200,000 and 90,000, respectively).
...
PMID:Two malic enzymes in Pseudomonas aeruginosa. 414 45

Fat-cells were prepared from rat and guinea-pig epididymal adipose tissue and compared on the basis of the intracellular distributions and activities of enzymes and with respect to their utilization of various U-(14)C-labelled substrates for lipogenesis. 1. Compared with the rat, guinea-pig extramitochondrial enzyme activities differed in that aconitate hydratase, alanine aminotransferase, ATP-citrate lyase, lactate dehydrogenase, NAD-malate dehydrogenase, NADP-malate dehydrogenase and phosphoenolpyruvate carboxykinase activities were appreciably lower, whereas aspartate aminotransferase, glucose 6-phosphate dehydrogenase, NADP-isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase activities were appreciably higher. Mitochondrial activities of citrate synthase, NADP-isocitrate dehydrogenase and pyruvate carboxylase were appreciably lower, whereas mitochondrial activities of aspartate aminotransferase, glutamate dehydrogenase, NAD-malate dehydrogenase and phosphoenolpyruvate carboxykinase were higher in the guinea pig compared with the rat. 2. In general guinea-pig fat-cells incorporated acetate and lactate into fatty acids more readily than rat fat-cells, whereas rat fat-cells incorporated glucose and pyruvate more readily than guinea-pig fat-cells. 3. Acetate stimulated the incorporation of glucose into fatty acids in rat fat-cells, but had no appreciable effect upon this process in guinea-pig fat-cells. Acetate greatly decreased the incorporation of lactate into fatty acids in cells from both species. 4. Lactate/pyruvate ratios produced by incubation of guinea-pig cells with glucose+insulin were very low compared with those found with rat cells under the same conditions. 5. With glucose (+insulin) or with glucose+acetate (+insulin) as substrates guinea-pig cells produced enough NADPH by the hexose monophosphate pathway to satisfy the NADPH requirements of lipogenesis. In rat fat-cells under the same conditions, hexose monophosphate-pathway NADPH provision was not sufficient to meet the requirements of lipogenesis. 6. These results are discussed, particularly in relationship to the disposition of cytosolic reducing equivalents in the cells.
...
PMID:Lipogenesis in rat and guinea-pig isolated epididymal fat-cells. 415 67

Factors influencing the utilization of ketone bodies by mouse adipose tissue in vitro were studied. Epididymal fat pads can oxidize DL-Beta-hydroxybutyrate-3-(14)C and acetoacetate-3-(14)C to (14)CO(2) as well as convert these compounds to fatty acid-(14)C. An increased output of (14)CO(2) from Beta-hydroxybutyrate-3-(14)C was noted in response to glucose plus insulin, succinate, oxaloacetate, L-asparate, and L-malate. Fatty acid synthesis from Beta-hydroxybutyrate was enhanced by glucose plus insulin, L-aspartate, L-malate, oxaloacetate, and citrate. Nicotinamide stimulated the oxidation of Beta-hydroxybutyrate but not of acetoacetate to CO(2), and did not affect fatty acid synthesis from either ketone body. Nicotinamide increased NAD(+) and NADP(+) levels in epididymal fat pads without affecting the concentration of NADH and NADPH. "Superlipogenesis" caused by fasting the mice for 48 hr and re-feeding them for 24 hr sharply enhanced CO(2) output and lipogenesis from Beta-hydroxybutyrate. The activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, NADP-malic dehydrogenase, and citrate cleavage enzyme from mouse adipose tissue were increased during "superlipogenesis." Free fatty acid release by epididymal fat pads in vitro was slightly increased by Beta-hydroxybutyrate. The relationship of ketone body metabolism and lipogenesis in adipose tissue is discussed.
...
PMID:Factors influencing the utilization of ketone bodies by mouse adipose tissue. 422 Nov 4

1. Activities of glucose 6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), isocitrate dehydrogenase (EC 1.1.1.42), malate dehydrogenase (EC 1.1.1.37), malate dehydrogenase (decarboxylating) (EC 1.1.1.40), and pyruvate carboxylase (EC 6.4.1.1) were determined in subcellular fractions of mammary gland from rabbits during pregnancy, at different stages of lactation and during weaning. The results were compared with those obtained in similar experiments with rat mammary gland. 2. Three bases of expression of the activity of enzymes in the particle-free supernatant fraction of mammary gland were compared. During lactation, activity expressed per mg. of particle-free supernatant protein (uncorrected for milk protein) correlated well with that expressed per mug. of DNA phosphorus. The disadvantages of expressing activities per g. wet wt. are discussed. 3. The major differences between the two tissues were: (a) neither malate dehydrogenase (decarboxylating) nor a soluble form of pyruvate carboxylase could be detected in rabbit mammary gland at any stage of the lactation cycle; (b) isocitrate dehydrogenase increased in activity during lactation in rabbit mammary gland, but not in that of the rat. 4. Pyruvate carboxylase in the mitochondrial fraction of rabbit mammary gland, and in both the mitochondrial and the soluble fractions of rat mammary gland, did not change in activity during lactation. 5. For each tissue, the NADP-dependent dehydrogenases studied had a high activity at all stages of the lactation cycle compared with the rate of fatty acid synthesis at mid-lactation. The significance of these results is discussed with respect to the supply of NADPH via NADH.
...
PMID:Enzymic changes in rabbit and rat mammary gland during the lactation cycle. 438 22

1. Superovulated rat ovary was found to contain high activities of NADP-malate dehydrogenase and NADP-isocitrate dehydrogenase. The activity of each enzyme was approximately four times that of glucose 6-phosphate dehydrogenase and equalled or exceeded the activities reported to be present in other mammalian tissues. Fractionation of a whole tissue homogenate of superovulated rat ovary indicated that both enzymes were exclusively cytoplasmic. The tissue was also found to contain pyruvate carboxylase (exclusively mitochondrial), NAD-malate dehydrogenase and aspartate aminotransferase (both mitochondrial and cytoplasmic) and ATP-citrate lyase (exclusively cytoplasmic). 2. The kinetic properties of glucose 6-phosphate dehydrogenase, NADP-malate dehydrogenase and NADP-isocitrate dehydrogenase were determined and compared with the whole-tissue concentrations of their substrates and NADPH; NADPH is a competitive inhibitor of all three enzymes. The concentrations of glucose 6-phosphate, malate and isocitrate in incubated tissue slices were raised at least tenfold by the addition of glucose to the incubation medium, from the values below to values above the respective K(m) values of the dehydrogenases. Glucose doubled the tissue concentration of NADPH. 3. Steroidogenesis from acetate is stimulated by glucose in slices of superovulated rat ovary incubated in vitro. It was found that this stimulatory effect of glucose can be mimicked by malate, isocitrate, lactate and pyruvate. 4. It is concluded that NADP-malate dehydrogenase or NADP-isocitrate dehydrogenase or both may play an important role in the formation of NADPH in the superovulated rat ovary. It is suggested that the stimulatory effect of glucose on steroidogenesis from acetate results from an increased rate of NADPH formation through one or both dehydrogenases, brought about by the increases in the concentrations of malate, isocitrate or both. Possible pathways involving the two enzymes are discussed.
...
PMID:The role of nicotinamide-adenine dinucleotide phosphate-dependent malate dehydrogenase and isocitrate dehydrogenase in the supply of reduced nicotinamide-adenine dinucleotide phosphate for steroidogenesis in the superovulated rat ovary. 439 12

Catabolism of carbohydrates has been implicated in the regulation of aflatoxin synthesis. To characterize this effect further, the activities of various enzymes associated with glucose catabolism were determined in Aspergillus parasiticus organisms that were initially cultured in peptone-mineral salts medium and then transferred to glucose-mineral salts and peptone-mineral salts media. After an initial increase in activity, the levels of glucose 6-phosphate dehydrogenase, mannitol dehydrogenase, and malate dehydrogenase were lowered in the presence of glucose. Phosphofructokinase activity was greater in the peptone-grown mycelium, but fructose diphosphatase was largely unaffected by carbon source. Likewise, carbon source had relatively little effect on the activities of pyruvate kinase, malic enzyme, isocitrate-NADP dehydrogenase, and isocitrate-NAD dehydrogenase. The results suggest that glucose may, in part, regulate aflatoxin synthesis via a carbon catabolite repression of NADPH-generating and tricarboxylic acid cycle enzymes.
...
PMID:Regulation of aflatoxin biosynthesis: effect of glucose on activities of various glycolytic enzymes. 609 45

Two thioredoxin fractions had previously been reported to occur in Anabaena 7119 by Buchanan and co-workers (Yee, B. C., dela Torre, A., Crawford, N. A., Lara, C., Carlson, D. E., and Buchanan, B. B. (1981) Arch. Microbiol. 130, 14-18). These proteins were detected by their ability to activate spinach fructose-1,6-bisphosphatase (Fru-P2-ase). The partially purified proteins resembled similar thioredoxins found in spinach chloroplasts and were designated thioredoxin f (Tf) for the fraction most effective in activating spinach Fru-P2-ase and thioredoxin m (Tm) for the fraction most effective in activating spinach NADPH-malate dehydrogenase. Using the assay system of Yee and co-workers, we were able to separate and purify to homogeneity two thioredoxin fractions from Anabaena extracts. Tm corresponded to the thioredoxin fraction we had isolated and studied previously (Gleason, F. K., and Holmgren, A. (1981) J. Biol. Chem. 256, 8301-8309). The other fraction, Tf, was characterized further. Unlike the thioredoxins found in higher plants, the cyanobacterial thioredoxins do not appear to be related. Anabaena thioredoxin f has a Mr = 25,500 as compared to the more usual Mr = 12,000 for Tm. From a comparison of the amino acid composition, Tf is not obviously a dimer or otherwise related to Tm. Tf has one active center cystine disulfide. Anabaena Tf activates spinach Fru-P2-ase very efficiently but has very little activity with spinach malate dehydrogenase. Anabaena Tf, unlike Tm, does not reduce the homologous ribonucleotide reductase. Anabaena Tf also does not activate a partially purified preparation of Anabaena Fru-P2-ase. We conclude that the cyanobacterial Tf is a unique protein with no structural or functional properties in common with other thioredoxins.
...
PMID:Isolation and characterization of thioredoxin f from the filamentous cyanobacterium, Anabaena sp. 7119. 609 40

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.
...
PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7

When strain C3 of Klebsiella pneumoniae is grown on a minimal medium with excess glucose, isocitrate dehydrogenase, malate dehydrogenase, and succinate dehydrogenase specific activities increase in the last period of the exponential growth phase and in the beginning of the stationary phase. Glucose exhaustion does not alter the development of malate dehydrogenase and succinate dehydrogenase, but specific activities are higher than those obtained with excess glucose. In contrast, glucose exhaustion can be correlated with a decrease of isocitrate dehydrogenase specific activity in the stationary phase. Induction of strain C3 isocitrate dehydrogenase by glucose in complex medium and repression by cAMP in mineral medium were observed. Glucose induction and the NADP/NADPH ratio are suggested as regulatory mechanisms controlling isocitrate dehydrogenase synthesis in the Enterobacteriaceae, but the former appears to be restricted to some Klebsiella strains.
...
PMID:Effect of the carbon source and cyclic AMP on isocitrate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase in Klebsiella pneumoniae C3. 629 82

Resident peritoneal macrophages of the mouse, cultivated for 3 d, have been studied by quantitative subcellular fractionation using differential centrifugation and density equilibration in linear gradients of sucrose. Density equilibration experiments were carried out on untreated cytoplasmic extracts, on cytoplasmic extracts treated with digitonin or sodium pyrophosphate, and on cytoplasmic extracts derived from cells cultivated for 24 h in the presence of Triton WR-1339. The enzyme distributions obtained distinguished six typical behaviors characteristic of distinct subcellular entities. Acid alpha-galactosidase and other acid hydrolases displayed the highest average velocity of sedimentation and equilibrium density. Culturing in a medium that contained Triton WR-1339 markedly decreased their density, most likely as a result of Triton WR-1339 accumulation within lysosomes. Cytochrome c oxidase and the sedimentable activity of malate dehydrogenase showed a narrow density distribution centered around 1.17, very similar under all the experimental situations; their rate of sedimentation fell within the range expected for mitochondria. Catalase was particle-bound and exhibited structure-linked latency (80 percent); it was released in soluble and fully active form by digitonin, but this required a much higher concentration than in the case of lysosomal enzymes. Differences relative to all the other enzymes studied suggest the existence of a particular species of organelles, distinctly smaller than mitochondria, and possibly related to peroxisomes. Many enzymes were microsomal in the sense that the specific activities, but not the yields, were greater in microsomes than in other fractions obtained by differential centrifugation. These enzymes were distinguished in three groups by their properties in density equilibration experiments. NAD glycohydrolase, alkaline phosphodiesterase I, and 5'-nucleotidase had low equilibrium densities but became noticeably more dense after addition of digitonin. The other microsomal enzymes were not shifted by digitonin, in particular N-acetylglucosaminyltransferase and galactosyltransferase, which otherwise equilibrated at the same position in the gradient. We assign the digitonin-sensitive enzymes to plasma membranes and possibly to related endomembranes of the cells, and the two glycosyltransferases to elements derived from the Golgi apparatus. Finally, alpha-glucosidase, sulphatase C, NADH cytochrome c reductase, NADPH cytochrome c reductase, and mannosyltransferase, equilibrated at a relatively high density but were shifted to lower density values after addition of sodium pyrophosphate. These properties support their association with elements derived from the endoplasmic reticulum.
...
PMID:Analytical subcellular fractionation of cultivated mouse resident peritoneal macrophages. 630 Feb 79


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---