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 glycosomes of in vitro grown procyclic trypomastigote forms of Trypanosoma brucei were purified by three different procedures and the results compared by electron microscopy, enzyme assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Centrifugation on a self-forming Percoll gradient followed by a sucrose gradient centrifugation resulted in the least enriched glycosomal preparation. Centrifugation on a pre-formed Nycodenz gradient gave an improved preparation but the most homogeneous preparation of intact glycosomes was obtained after centrifugation on two successive sucrose gradients. Glycosomes purified by both the Nycodenz and double sucrose gradient procedures appeared larger than in situ glycosomes presumably due to an osmotic effect resulting from disruption of the granular matrix of the organelles. Nevertheless, there appears to be no loss of cisternal contents due to the swelling of the organelles. The glycosomes of the bloodstream form trypomastigotes purified by the same procedures show, however, no sign of swelling. A comparison of glycosomes purified from procyclic trypomastigotes and bloodstream form trypomastigotes prepared by the same double sucrose procedure demonstrated that in the glycosome of procyclic trypomastigotes: activities of hexokinase, phosphoglucose isomerase, phosphofructose kinase, aldolase and phosphoglycerate kinase and diminished by 80-100%; activities of glyceraldehyde-3-phosphate dehydrogenase, triose phosphate isomerase and glycerol-3-phosphate dehydrogenase remain unchanged or are only slightly reduced; there is an appearance of four major new proteins, among which could be phosphoenol pyruvate carboxykinase and malate dehydrogenase. These observations are in basic agreement with those by Hart et al. (Mol. Biochem. Parasitol. 12, 25-35, 1984).
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PMID:An improved purification of glycosomes from the procyclic trypomastigotes of Trypanosoma brucei. 380 43

Crude extracts of both vegetative cells and glycerol-induced microcysts of Myxococcus xanthus contained the following enzyme activities: phosphofructokinase, phosphoglucoisomerase, fructose-1,6-diphosphatase, fructosediphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate carboxylase, citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphoglucomutase, and uridine diphosphate glucose pyrophosphorylase. With the exception of isocitrate dehydrogenase, which was present at a fivefold higher concentration in microcysts, all activities in extracts from both types of cells were essentially equal. Hexokinase and pyruvate kinase could not be detected in extracts from either type of cell. Microcysts metabolized acetate at a lower rate than did vegetative cells. Most of this decrease was reflected in a substantial decrease in ability of microcysts to oxidize acetate to CO(2). In addition, microcysts and vegetative cells showed a different distribution of (14)C-label from incorporated acetate.
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PMID:Comparative intermediary metabolism of vegetative cells and microcysts of Myxococcus xanthus. 430 96

Octanoic acid inhibits, in vitro, the bacterial enzymes glucose-6-phosphate dehydrogenase, phosphofructokinase, pyruvate kinase, fumarase, lactate dehydrogenase, and the malic enzyme of Arthrobacter crystallopoietes. The free fatty acid appears to act as an inhibitor of lipogenesis, although it does not affect the rate of gluconeogenesis. To demonstrate that this inhibition may be of physiological significance in vivo, those enzymes not involved in lipogenesis, such as fructose-1, 6-diphosphatase, phosphoglucomutase, phosphohexoisomerase, aconitase, nicotinamide adenine dinucleotide phosphate (NADP) isocitrate dehydrogenase, NADP glutamate dehydrogenase, malate dehydrogenase, and isocitrate lyase, were assayed and found not to be inhibited by the free fatty acid.
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PMID:Selective inhibition of bacterial enzymes by free fatty acids. 430 71

The antigen that causes killing of at least 98% of a human cell population treated with a 1% solution of a specific rabbit antiserum in the presence of complement is a sensitive genetic marker. The rapid loss of human chromosomes in human-Chinese hamster cell hybrids makes possible a convenient test of linkage relationships with this marker. Hybrid clones with and without the lethal antigen were isolated and analyzed. In 76 clones and subclones studied, 41 carried both the lethal antigen and the lactic dehydrogenase-A marker, 35 carried neither, and no clones contained only one of the two markers. In contrast to this clear demonstration of linkage, absence of linkage was found between the lethal antigen and the following markers: Lactic dehydrogenase B, NAD-dependent malic dehydrogenase, NADP-dependent malic dehydrogenase, glucose-6-phosphate dehydrogenase, phosphoglucomutase, glutamate oxaloacetate transaminase, indophenol oxidase, glucose phosphate isomerase, proline, inositol, hypoxanthine B, and glycine A. This lethal antigen appears to be carried on a single human autosome.
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PMID:Genetics of somatic mammalian cells: lethal antigens as genetic markers for study of human linkage groups. 433 8

The effect of sodium selenite on the activity of the selected enzymes in blood serum and on mercury concentration in some tissues of guinea pigs exposed to ethyl- (EtHg) or phenylmercuric chloride (PhHg) was investigated. Every second day for a 3-month period animals were given intragastrically a solution of mercuric compounds (2.5 mg Hg/kg) with or without sodium selenite (1 mg Se/kg). The activity of malate dehydrogenase (MDH, EC 1.1.1.37), phosphohexoizomerase (PHI, EC 5.3.1.9), and gamma-glutamyltranspeptidase (GGTP, EC 2.3.2.2) in blood serum of control animals was ca. 3.8, 325, and 48 IU. After 10 weeks of exposure to EtHg and PhHg, the activities (IU) of the above enzymes were, respectively, 5.9 and 6.5 (MDH), 585 and 600 (PHI) and 211 and 86.5 (GGTP). Sodium selenite administered with mercuric compounds did not prevent in increases in enzyme activity. During the experiment the level of inorganic as well as organic mercury accumulated in kidneys and liver was estimated. After a 12-week exposure, sodium selenite decreased the level of total mercury in the liver (in the case of both EtHg and PhHg: from 47.0 to 31.8 and from 41.3 to 25.4 micrograms Hg/g tissue, respectively). It also slightly decreased the mercury level in the kidneys of animals exposed to PhHg (from 889 to 73.3 micrograms Hg/g tissue) but did not change the mercury concentration in the kidneys of guinea pigs exposed to ethylmercuric chloride.
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PMID:Activity of chosen indicator enzymes in blood serum of guinea pigs exposed to ethyl- and phenylmercuric chloride alone or jointly with sodium selenite. 613 38

The enzyme phosphoglucose isomerase (PGI), phosphoglucomutase (PGM), hexokinase (HK), adenylate kinase (AK), fructokinase (FK), mannose-6-phosphate isomerase (MPI), glucose-6-phosphate dehydrogenase (G-6-PDH) and malate dehydrogenase (MDH) were chosen to study the variation between isolates, cercariae and adults, individuals, and sexes of Schistosoma mansoni and S. rodhaini, using horizontal polyacrylamide gel electrophoresis. The method described allows combinations of six of the eight enzymes to be scored in the homogenate from one adult worm. In adult S. mansoni one phenotype of the eight enzymes was observed in all isolates. In addition, the enzyme PGI showed polymorphism in the isolates from Tala, Kenya and Uganda. PGM in the isolates from Tala, Kenya and South Africa showed polymorphism. The cercarial phenotype differs from the adult phenotype in G-6-PDH, where the cercarial enzyme mobility is slower than that in the adult worm. The low amount of intrastrain variation observed in this species is explained by the limited amount of material used to establish the laboratory stocks, whereas the genetic similarity between geographically widely separated stocks does suggest that only limited geographical variation is likely to occur in S. mansoni. It is suggested that the gene controlling the PGI polymorphism is located on the sex chromosomes of S. mansoni. Mobility differences were observed between S. mansoni and S. rodhaini in the enzyme PGI and PGM, and these characteristics might be useful for a quick identification of schistosome cercariae emerging from Biomphalaria sp. in Africa.U
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PMID:Isoenzyme studies on cercariae from monoinfections and adult worms of Schistosoma mansoni (10 isolates) and S. rodhaini (one isolate) by horizontal polyacrylamide gel electrophoresis and staining of eight enzymes. 621

The genetic relationships within and between stocks of Trypanosoma cruzi were studied by the in vitro isolation of clones and sub-clones and by the comparison of their isoenzyme patterns in thin-layer starch-gel electrophoresis. Altogether 13 clones and 36 sub-clones were isolated from stocks CL89 and Y207 of T. cruzi. Employing the enzymes L-alanine aminotransferase (ALAT), L-aspartate aminotransferase (ASAT), glucose phosphate isomerase (GPI), malic enzyme (ME), malate dehydrogenase (MDH), glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), and phosphoglucomutase (PGM), two zymodemes, B and C, emerged among the clones with distinct banding patterns. These zymodemes were consistently distinguished by ALAT, ASAT, GPI, G6PD, 6PGD, and PGM and the differences in enzyme profiles were simultaneously reflected in all six enzyme systems. That the enzymic characters as genetic determinants are stable was demonstrated after recloning and successive replica-platings, i.e., the distinct enzyme patterns remained consistent and homogeneous, the siblings retained the enzyme profiles of their parental clones, and no segregation of the enzyme patterns was observed. Our data from clone and sub-clone examinations show that the isoenzymes act as labels to characterize T. cruzi stocks. Furthermore, enzyme variation was demonstrated among clones isolated from stock CL89.
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PMID:Enzyme variation among clones of Trypanosoma cruzi. 621 97

The extent of naturally occurring variations of enzyme locus expression was determined for three tissues (liver, muscle, and eye) in two species of sunfish (Centrarchidae), the green sunfish (Lepomis cyanellus) and the redear sunfish (L. microlophus). The genetic basis for species differences in tissue enzyme specific activities of malate dehydrogenase (EC 1.1.1.37), lactate dehydrogenase (EC 1.1.1.27), phosphoglucomutase (EC 2.7.5.1), and glucosephosphate isomerase (EC 5.3.1.9) was investigated by determining enzyme specific activities in the tissues of the reciprocal F1 hybrids and of their backcross progenies. The specific activities for most enzymes in hybrids were intermediate between those of the parental species. Significant differences in enzyme specific activity were detected among the F1 progeny as well as those of backcrosses. Variations in specific activity levels in one tissue were often independent of variations in specific activities in a different tissue. However, the changes in the specific activities of different enzymes within the same tissue were often positively correlated. The tissue glucosephosphate isomerase activity differences appear not to be due to different functional contributions of the glucosephosphate isomerase allelic isozymes. Cluster analysis of distributions of specific activities revealed no simple Mendelian pattern of inheritance for control of tissue enzyme activity. Our results suggest a polygenic control of tissue enzyme specific activity levels.
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PMID:Differences in tissue expressions of enzyme activities in interspecific sunfish (Centrarchidae) hybrids and their backcross progeny. 624 Feb 60

In this preliminary report, we describe a polyacrylamide gel electrophoresis technique for the resolution of isoenzyme patterns of four isolates of Entamoeba histolytica and one isolate of Entamoeba coli. Our findings were similar to previous findings for three enzyme systems: maleic enzyme (malate dehydrogenase [EC 1.1.1.40]), hexokinase (EC 2.7.1.1), and phosphoglucomutase (EC 2.7.5.1). We found preliminary evidence that glucosephosphate isomerase (EC 5.3.1.9) may also differentiate invasive amoebae from noninvasive amoebae, when the isoenzymes are separated by polyacrylamide gel electrophoresis, whereas this differentiation is not evident with starch-gel electrophoresis. We used an Rf system to relate isoenzyme band mobility to the migration distance of a standard E. histolytica strain (HK-9). The numerical identification of isoenzyme bands can simplify the grouping of isolates into zymodemes.
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PMID:Polyacrylamide gel electrophoresis of isoenzymes from Entamoeba species. 630 37

Experimental conditions have been elaborated to test for reversibility of the malate dehydrogenase inactivation (E.C.1.1.1.37) after addition of glucose to derepressed yeast cells. Malate dehydrogenase inactivation was shown to be irreversible at all stages of inactivation. In contrast fructose-1,6-bisphosphatase inactivation (E.C.3.1.11) remained reversible for at least 30 min after addition of glucose. Rapid reversible inactivation of fructose-1,6-bisphosphatase and irreversible inactivation of malate dehydrogenase were additionally investigated in glycolytic block mutants. Normal inactivation kinetics were observed in mutants without catalytic activity of phosphoglucose isomerase (E.C.5.3.1.9), phosphofructokinase (E.C.2.7.1.11), triosephosphate isomerase (E.C.5.3.1.1) and phosphoglycerate kinase (E.C.2.7.2.3). Hence, neither type of inactivation depended on the accumulation of any glucose metabolite beyond glucose-6-phosphate. Under anaerobic conditions irreversible inactivation was completely abolished in glycolytic block mutants. In contrast rapid reversible inactivation was independent of energy provided by respiration or fermentation. Reversibility of fructose-1,6-bisphosphatase inactivation was tested under conditions which prevented irreversible malate dehydrogenase inactivation. In these experiments, fructose-1,6-bisphosphatase inactivation remained reversible for at least 120 min, whereas reversibility was normally restricted to about 30 min. This indicated a common mechanism between the irreversible part of fructose-1,6-bisphosphatase inactivation and irreversible malate dehydrogenase inactivation.
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PMID:Studies on rapid reversible and non-reversible inactivation of fructose-1,6-bisphosphatase and malate dehydrogenase in wild-type and glycolytic block mutants of Saccharomyces cerevisiae. 631 Nov 31


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