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

The isolation is described of pure cultures of three non-methane-utilizing methylotrophic bacteria which, together with the previously described Bacillus PM6, have a very limited range of growth substrates; these organisms are designated "restricted facultative' methylotrophs. Two of these isolates, W6A and W3A1, grow only on glucose out of 50 non-C1 compounds tested, whereas the third isolate S2A1 and Bacillus PM6 grow on betaine, glucose, gluconate, alanine, glutamate, citrate and nutrient agar, but not on any of a further 56 non-C1 compounds. Crude sonic extracts of trimethylamine-grown and glucose-grown W6A and W3A1 isolates, and of trimethylamine-grown C2A1 (an obligate methylotroph) contain (i) no detectable 2-oxogltarate dehydrogenase activity, (ii) very low or zero specific activities of succinate dehydrogenase and succinyl-CoA synthetase and (iii) NAD+-dependent isocitrate dehydrogenase activity. Extracts of trimethylamine-grown PM6 and S2A1 methylotrophs have (i) very low 2-oxoglutarate dehydrogenase specific activities, (ii) comparatively high specific activities of succinate dehydrogenase, malate dehydrogenase and succinyl-CoA synthetase and (iii) NADP+-dependent isocitrate dehydrogenase activity but no NAD+-dependent isocitrate dehydrogenase activity. The activities of most of these enzymes are increased during growth on glucose, alanine, glutamate or citrate, but only very low 2-oxoglutarate dehydrogenase activities are present under all growth conditions. The restricted facultative methylotrophs grow on certain non-C1 compounds in the absence of 2-oxoglutarate dehydrogenase and, in some cases, of other enzymes of the tricarboxylic acid cycle; these lesions cannot therefore be the sole cause of obligate methylotrophy.
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PMID:Tricarboxylic acid-cycle and related enzymes in restricted facultative methylotrophs. 0 Sep 91

Metabolism of lactate as a carbon source by Pseudomonas citronellolis occurred via a nicotinamide adenine dinucleotide (NAD)-independent L-lactate dehydrogenase, which was present in cells grown on DL-lactate but was not present in cells grown on acetate, aspartate, citrate, glucose, glutamate, or malate. The cells also possessed a constitutive, NAD-independent malate dehydrogenase instead of the conventional NAD-dependent malate dehydrogenase instead of the conventional NAD-dependent enzyme in the tricarboxylic acid cycle. Both enzymes were particulate and used dichlorophenolindo-phenol or oxygen as an electron acceptor. In acetate-grown cells, the activity of pyruvate dehydrogenase and NAD phosphate-linked malate enzyme decreased, cells grown on glucose or lactate. This was consistent with the need to maintain a supply of oxalacetate for metabolism of acetate via the tricarboxylic acid cycle. Changes in enzyme activities suggest that gluconeogenesis from noncarbohydrate carbon sources occurs via the malate enzyme (when oxalacetate decarboxylase is inhibited) or a combination of the NAD-independent malate dehydrogenase and oxalacetate decarboxylase.
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PMID:Formation and dissimilation of oxalacetate and pyruvate Pseudomonas citronellolis grown on noncarbohydrate substrates. 1 74

Glutamine synthetase (EC 6.3.1.2) was localized within the matrix compartment of avian liver mitochondria. The submitochondrial localization of this enzyme was determined by the digitonin-Lubrol method of Schnaitman and Greenawalt (35). The matrix fraction contained over 74% of the glutamine synthetase activity and the major proportion of the matirx marker enzymes, malate dehydrogenase (71%), NADP-dependent isocitrate dehydrogenase (83%), and glutamate dehydrogenase (57%). The highest specific activities of these enzymes were also found in the matrix compartment. Oxidation of glutamine by avian liver mitochondria was substantially less than that of glutamate. Bromofuroate, an inhibitor of glutamate dehydrogenase, blocked oxidation of glutamate and of glutamine whereas aminoxyacetate, a transaminase inhibitor, had little or no effect with either substrate. These results indicate that glutamine metabolism is probably initiated by the conversion of glutamine to glutamate rather than to an alpha-keto acid. The localization of a glutaminase activity within avian liver mitochondria plus the absence of an active mitochondrial glutamine transaminase is consistent with the differential effects of the transaminase and glutamate dehydrogenase inhibitors. The high glutamine synthetase activity (40:1) suggests that mitochondrial catabolism of glutamine is minimal, freeing most of the glutamine synthesized for purine (uric acid) biosynthesis.
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PMID:Submitochondrial localization and function of enzymes of glutamine metabolism in avian liver. 1 18

A system of enzymes is required for the transport of reducing equivalents from reduced nicotinamide adenine dinucleotide (NADH) generated in the cytosol into the mitochondria by the substrate cycles. Also, the intestinal mitochondria must be capable of oxidizing the substrates of the cycles. Both substrate cycle enzymes and permeable mitochondria are necessary for the flow of pyruvate derived from glucose into the mitochondria for oxidative decarboxylation and for the efficient production of adenosine 5'-triphosphate (ATP) for the unique intestinal nutrient transport functions. Mitochondria from hamster intestinal mucosa were prepared exhibiting good respiratory control ratios. The isolated intestinal mitochondria would not oxidize NADH unless N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was added as a carrier of reducing equivalents. The rates of oxidation of the substrates of the L-glycerol 3-phosphate and the L-malate/1-aspartate substrate cycles were measured with the mitochondria isolated from the small intestinal mucosa. The key enzymes measured in the cytosol and mitochondria from the mucosa were NAD-L-glycerol 3-phosphate dehydrogenase, Fp-L-glycerol 3-phosphate dehydrogenase, L-malate dehydrogenase and L-glutamate-oxaloacetate transaminase. In addition, the substrate cyclase were simulated in vitro by following NADH oxidation by isolated mitochondria in the presence of added cytosolic constituents.
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PMID:Flow of reducing equivalents into isolated intestinal mitochondria. 3 19

Adaptation of Ehrlich ascites tumor cells to serial cultivation in media with progressively elevated (hypertonic) NaCl content ("high NaCl"-tolerant cells) has resulted in progressive increases of the cellular activities of NAD-dependent glycerol-3-phosphate dehydrogenase (EC 1.1.1.8), NAD-dependent malate dehydrogenase (EC 1.1.1.37), glutamate--oxalacetate transaminase (EC 2.6.1.1), NAD (P)-dependent glutamate dehydrogenase (EC 1.4.1.3), NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42). The activities of glutamate-pyruvate transaminase (EC 2.6.1.2.) and of glycolytic enzymes as phospho-fructokinase (EC 2.7.1.11), glyceraldehydephosphate dehydrogenase (EC 1.2.1.12) and lactate dehydrogenase (EC 1.1.1.27) were only slightly and not in progressive manner (in response to the progressive increase of the environmental NaCl concentration) affected. These changes are discussed with respect to a metabolic pattern of these "high NaCl"-tolerant cells which is compatible with increased energy requirements, especially for active cation transport. It is suggested that these increased cellular enzyme activities reflect an increased transfer of reducing equivalents across mitochondrial membranes (via the "glycerophosphate cycle and the malate-aspartate shuttle") and possibly a stimulated lipid metabolism. These alterations in the level of enzyme activities must be regarded asan adaptive cellular response to the "high NaCl" environment, since readaptation to growth in regular isotonic media resulted in a reversion to the enzyme pattern characteristic of the parent cells.
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PMID:Changes in enzyme pattern of Ehrlich ascites tumor cells following serial cultivation in media with increased (hypertonic) NaCl content. 12 1

1. The subcellular distribution of adenine nucleotides, acetyl-CoA, CoA, glutamate, 2-oxoglutarate, malate, oxaloacetate, pyruvate, phosphoenolpyruvate, 3-phosphoglycerate, glucose 6-phosphate, aspartate and citrate was studied in isolated hepatocytes in the absence and presence of glucagon by using a modified digitonin procedure for cell fractionation. 2. In the absence of glucagon, the cytosol contains about two-thirds of cellular ATP, some 40-50% of ADP, acetyl-CoA, citrate and phosphoenolpyruvate, more than 75% of total 2-oxoglutarate, glutamate, malate, oxaloacetate, pyruvate, 3-phosphoglycerate and aspartate, and all of glucose 6-phosphate. 3. In the presence of glucagon the cytosolic space shows an increase in the content of malate, phosphoenolpyruvate and 3-phosphoglycerate by more than 60%, and those of aspartate and glucose 6-phosphate rise by about 25%. Other metabolites remain unchanged. After glucagon treatment, cytosolic pyruvate is decreased by 37%, whereas glutamate and 2-oxoglutarate decrease by 70%. The [NAD(+)]/[NADH] ratios calculated from the cytosolic concentrations of the reactants of lactate dehydrogenase and malate dehydrogenase were the same. Glucagon shifts this ratio and also that of the [NADP(+)]/[NADPH] couple towards a more reduced state. 4. In the mitochondrial space glucagon causes an increase in the acetyl-CoA and ATP contents by 25%, and an increase in [phosphoenolpyruvate] by 50%. Other metabolites are not changed by glucagon. Oxaloacetate in the matrix is only slightly decreased after glucagon, yet glutamate and 2-oxoglutarate fall to about 25% of the respective control values. The [NAD(+)]/[NADH] ratios as calculated from the [3-hydroxybutyrate]/[acetoacetate] ratio and from the matrix [malate]/[oxaloacetate] couple are lowered by glucagon, yet in the latter case the values are about tenfold higher than in the former. 5. Glucagon and oleate stimulate gluconeogenesis from lactate to nearly the same extent. Oleate, however, does not produce the changes in cellular 2-oxoglutarate and glutamate as observed with glucagon. 6. The changes of the subcellular metabolite distribution after glucagon are compatible with the proposal that the stimulation of gluconeogenesis results from as yet unknown action(s) of the hormone at the mitochondrial level in concert with its established effects on proteolysis and lipolysis.
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PMID:Effect of glucagon on metabolite compartmentation in isolated rat liver cells during gluconeogenesis from lactate. 19 59

Lability of NADP- and NAD-dependent glutamate dehydrogenases and malate dehydrogenases has been demonstrated during a change of the physiological activity of yeast Candida guilliermondii in the exponential phase of growth. Variations in the isoenzyme spectrum of the enzymes and total dehydrogenase activity of the yeast has been found during their transition from the accumulative to the continuous cultivation. Changes in the physiological state of yeast during their growth are accompanied by a rearrangement of the isoenzyme spectrum of malate dehydrogenase and glutamate dehydrogenases.
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PMID:[Activity of certain dehydrogenases in accumulation and continuous-flow culture of paraffin-oxidizing yeast of the genus Candida]. 24 90

Six strains of Rickettsia prowazekii, two derived from human infections and four isolated from flying squirrels, two strains of R. typhi, and the single available strain of R. canada, were characterized by several biochemical procedures. The electrophoretic patterns on polyacrylamide gels of rickettsial proteins solubilized by sodium dodecyl sulfate revealed several species differences, but strains of the same species appeared to have identical patterns. Cytoplasmic fractions of the rickettsiae were examined for enzymatic activities and for polyacrylamide gel isoelectric focusing patterns. Some species differences were encountered in the activities or ratios of activities of glutamate-oxaloacetate transaminase, glutamate dehydrogenase, and malate dehydrogenase. When polyacrylamide gels were stained for malate dehydrogenase after electrophoresis, a single band became apparent with single extracts or mixtures of two strains of R. prowazekii, but two bands were seen with mixtures of a strain of R. prowazekii and one of R. typhi. The isoelectric focusing patterns of the soluble proteins revealed numerous species differences, especially between R. canada and the other two species, and a few differences among the strains of R. prowazekii. The patterns of the two human strains, Breinl and E(R), differed in at least one location, and both differed from the flying squirrel strains in the displacement of one band. One of the flying squirrel strains, GvF-16, contained a protein band not seen in the other five strains. Despite these minor differences, a striking similarity was revealed by all the biochemical tests performed between the R. prowazekii strains of human and flying squirrel origin.
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PMID:Biochemical characteristics of typhus group rickettsiae with special attention to the Rickettsia prowazekii strains isolated from flying squirrels. 41 82

Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)-deficient mutants of a bovine kidney cell line (MDBK) were selected following mutagenesis with ethylmethane sulfonate or ICR-170G. MDBK mutants were hybridized to thymidine kinase-deficient L cells and selected in HAT medium. Parental and hybrid cells were characterized for isozyme patterns of lactic dehydrogenase malate dehydrogenase, glucose-6-phosphate dehydrogenase, and glutamate oxalate transaminase. Chromosomes of MDBK can be distinguished from mouse L cells by configuration and by fluorescent staining with Hoechst 33-258 stain. Hybrid cells contained both MDBK and L-cell chromosomes and had elevated DNA content. MDBK cells are normally restrictive for mengovirus replication. Both permissive and restrictive hybrids were found. Our data indicate that there was preferential loss of MDBK chromosomes in the hybrid cell lines.
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PMID:Characterization of hybrids between bovine (MDBK) and mouse (L-cell) cell lines. 45 55

1. The presence of glutamate dehydrogenase in the microsomal fraction of rat liver was confirmed. The identities of mitochondrial and microsomal glutamate dehydrogenases were proved by immunochemical methods and by SDS polyacrylamide gel electrophoresis of purified enzymes. 2. Synthesis of glutamate dehydrogenase by the membrane-bound ribosomes of rough endoplasmic reticulum was determined. Newly synthesized enzyme molecules were discharged on the cytoplasmic surface of endoplasmic reticulum membranes. 3. A precursor-product relationship was found between microsomal and mitochondrial glutamate dehydrogenases. About six hours were needed for the transport of glutamate dehydrogenase from the site of synthesis to mitochondria. 4. The half-life of glutamate dehydrogenase was about 5.5 days, which was somewhat longer than that of mitochondrial total protein determined in the same experiment. 5. Mitochondrial-type malate dehydrogenase was also present in the microsomal fraction. Subfractionation of smooth microsomes revealed the existence of particular light microsomal vesicles in which both glutamate dehydrogenase and malate dehydrogenase were concentrated. These vesicles may participate in intracellular transport of matrix enzymes from microsomes to mitochondria.
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PMID:Biogenesis of the mitochondrial matrix enzyme, glutamate dehydrogenase, in rat liver cells. I. Subcellular localization, biosynthesis, and intracellular translocation of glutamate dehydrogenase. 59 7


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