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)

Setaria cervi, the filarial parasite inhabiting the Indian water buffalo (Bubalus bubalis Linn.) contained almost all the enzymes involved in glycogen degradation. Significant activities of glycogen phosphorylase, glucokinase, phosphoglucomutase, phosphoglucose isomerase, phosphofructokinase, FDP-aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate hydratase, pyruvate kinase, lactate dehydrogenase glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were detected in cell-free extracts of whole worms. The presence of PEP-carboxykinase, malate dehydrogenase, fumarase and fumarate reductase revealed the functioning of the PEP-succinate pathway in addition to phosphorylating glycolysis and pentose phosphate pathway in the parasite. Excepting fumarate reductase all other enzymes were localized in the particulate-free cytosol fraction, although small amounts of glycogen phosphorylase, aldolase and lactate dehydrogenase were also detected in the mitochondrial fraction.
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PMID:Setaria cervi: enzymes of glycolysis and PEP-succinate pathway. 86 May 72

Male outbred Sprague-Dawley rats were fed a choline-deficient diet containing 0.10% DL-ethionine (CDE) for 4, 6, 10, 14 or 22 weeks followed by a standard diet for up to 59 weeks. Liver sections were histochemically analyzed for the following parameters: basophilia, glycogen content and the activities of glycogen synthase (SYN), glycogen phosphorylase (PHO), glucose-6-phosphatase (G6PASE), glucose-6-phosphate dehydrogenase (G6PDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerin-3-phosphate dehydrogenase (G3PDH), 'malic enzyme' (MDH), alkaline phosphatase (ALKPASE) and gamma-glutamyltranspeptidase (GGT). The stop experiments revealed that many of the oval cells proliferating during the first 4-6 weeks may undergo necrotic changes and disappear with time, whereas cholangiofibroses appearing in animals fed CDE for at least 10 weeks are persistent lesions. The sequence of lesions seen in this study, leading from persistent oval cells through cholangiofibroses to cholangiofibromas, strongly suggests that the oval cells are the precursor cells of cholangiocellular tumors. The proliferating oval cells and the hepatic foci consisting of clear and acidophilic or mixed cell populations were always spatially separated and no transitions between oval and parenchymal cells were observed. These results argue against a precursor-product relationship between oval and parenchymal cells. Both proliferating and persistent oval cells, cholangiofibroses and cholangiofibromas showed a strong staining for G6PDH, GAPDH, G3PDH, MDH, ALKPASE and GGT; low PHO, SYN and G6PASE activities were also detected in these lesions. Persistent glycogen-storage foci, which developed in all rats fed CDE for 4-14 weeks followed by a normal lab chow for over a year, had increased PHO, G6PDH, MDH, ALKPASE and GGT activities, while SYN, GAPDH and G3PDH activities remained unaltered and G6PASE activity decreased. Mixed cell foci appearing in animals fed CDE for 22 weeks followed by a normal lab chow for 59 weeks had strongly increased G6PDH, GAPDH, G3PDH, MDH, ALKPASE and GGT activities as well as decreased G6PASE activity. These results indicate that the characteristic metabolic pattern of preneoplastic hepatic foci is independent of the further administration of the carcinogenic diet. The shift from glycogen metabolism to glycolysis and the pentose phosphate pathway occurring during the later stages of CDE-induced hepatocarcinogenesis is an autogenous process apparently directing the disturbed carbohydrate metabolism towards alternative metabolic pathways. A similar metabolic shift also seems to take place during cholangiocarcinogenesis.
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PMID:Persistence of the cholangiocellular and hepatocellular lesions observed in rats fed a choline-deficient/DL-ethionine-supplemented diet. 131 Sep 7

Renal clear cell tubules and clear/acidophilic cell tumors were induced in male Sprague-Dawley rats by 7 weeks oral administration (stop model) of N-nitrosomorpholine (NNM) at a concentration of 12 mg/100 ml in the drinking water. Twelve, 23 and 34 weeks after withdrawal of NNM serial cryostat sections of the kidneys were histochemically analyzed for the following parameters: glucose transporter proteins (GLUT1, GLUT2), glycogen content and the activities of glycogen synthase (SYN), glycogen phosphorylase (PHO), glucose-6-phosphatase (G6Pase), glucose-6-phosphate dehydrogenase (G6PDH), hexokinase (HK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase (PK), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), alkaline phosphatase (ALP), acid phosphatase (ACP) and gamma-glutamyltransferase (GGT). Clear cell (glycogenotic) tubules first appeared at 23 weeks, and clear/acidophilic cell tumors at 34 weeks after withdrawal of the carcinogen. G6Pase, ALP, GGT and GLUT2 were absent in clear cell tubules, clear/acidophilic cell tubules, and clear/acidophilic cell tumors indicating a sequential origin of all these types of lesions from the collecting duct system, in line with previous morphological findings. In comparison to the collecting duct epithelium, glycogenotic tubules demonstrated an increased activity of PHO and reduced activities of glycolytic and mitochondrial enzymes, which were accompanied by a strongly reduced expression of GLUT1. Moderately increased activities of glycolytic and mitochondrial enzymes were observed in the clear cells of clear/acidophilic cell tubules and tumors compared with those in glycogenotic tubules. They had slightly increased activities of the glycolytic enzymes GAPDH and PK compared with normal collecting duct epithelium, while most of them were nearly lacking in GLUT1. Our findings suggest that glycogen storage is not due to an increased uptake of glucose from the blood, but results from a disturbance in intracellular flux of metabolites. The development of clear cell tubules from the normal collecting duct epithelium is accompanied by a markedly decreased expression of GLUT1 along with a reduction in glycolytic and mitochondrial enzymes. This reduction of enzyme activities is replaced by an increase in enzyme activities in clear/acidophilic cell tumors indicating a fundamental shift in carbohydrate metabolism during progression from preneoplastic to neoplastic lesions.
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PMID:Sequential changes in glycogen content, expression of glucose transporters and enzymic patterns during development of clear/acidophilic cell tumors in rat kidney. 147 41

Male outbred Sprague-Dawley rats were fed a choline-deficient diet containing 0.10% DL-ethionine for up to 30 weeks. Liver slices from rats killed 4, 6, 10, 14, 22 and 30 weeks after starting the treatment were histochemically analyzed for the following parameters: basophilia, expression of cytokeratin 19 (which in the liver is bile duct epithelial cell-specific), glycogen content and activities of glycogen synthetase (SYN), glycogen phosphorylase (PHO), glucose-6-phosphatase (G6PASE), glucose-6-phosphate dehydrogenase (G6PDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerin-3-phosphate dehydrogenase (G3PDH), 'malic enzyme' (MDH), alkaline phosphatase (ALKPASE) and gamma-glutamyltranspeptidase (GGT). The diet induced necrosis of single parenchymal cells and a massive proliferation of oval cells within 4-6 weeks; thereafter cholangiofibroses, cystic cholangiomas and some cholangiofibromas, but no cholangiocarcinomas, were observed. Oval cells, cholangiofibroses, cystic cholangiomas and cholangiofibromas expressed cytokeratin 19, whereas parenchymal cells, foci of altered hepatocytes and hepatocellular adenomas did not; this observation does not support a precursor-product relationship between oval and parenchymal cells. SYN, PHO, G6PASE, G6PDH, GAPDH, G3PDH, MDH, ALKPASE and GGT activities were detected in oval cells; cholangiofibrotic lesions, cystic cholangiomas and cholangiofibromas stained strongly for GAPDH, G3PDH and MDH. In livers from rats fed the diet for 10 weeks, single hepatocytes storing high amounts of glycogen appeared in the parenchyma. There was no indication of a transition from the oval cell population to hepatocytes storing glycogen in excess. Foci of glycogen-storing cells were scattered all over the lobes after 14 and 22 weeks; they had increased G6PASE, G6PDH, ALKPASE and GGT activities. Mixed cell foci and hepatocellular adenomas developed within 22-30 weeks and exhibited a remarkable decrease of G6PASE activity, a strong increase of G6PDH, GAPDH, G3PDH and MDH activities as well as extremely high ALKPASE and GGT activities. The data support the concept that during hepatocarcinogenesis, a number of sequential changes in the activities of various enzymes involved in carbohydrate metabolism occur and that a correlation between morphology and enzyme pattern in the focal lesions does in fact exist. Furthermore, our results suggest that two different cell lineages are involved in the development of cholangiocellular tumors from oval cells and hepatocellular tumors from hepatocytes.
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PMID:Enzyme histochemical and immunohistochemical characterization of oval and parenchymal cells proliferating in livers of rats fed a choline-deficient/DL-ethionine-supplemented diet. 170 20

The chronically active (pseudomyotonic) gastrocnemius muscle in the C57B16J dy2J/dy2J mouse contains both elevated lactate and glycogen as well as fibers that have high amounts of glycogen and enhanced glyconeogenic activity. In the present study we analyze the activities of some key glyconeogenic enzymes to assess the causes of elevated muscle glycogen and to determine the pathway for glycogen synthesis from lactate. Glycogen synthase, malate dehydrogenase, phosphoenolpyruvate carboxykinase, and malic enzyme were all elevated in homogenates of the chronically active muscle. Activities of glycogen phosphorylase and fructose 1,6-bisphosphatase were decreased in whole muscle homogenates. Histochemistry demonstrated that the high-glycogen fibers were typically fast-twitch glycolytic fibers that had high glycogen synthase, glycogen phosphorylase, and malic enzyme activities. Malate dehydrogenase activity followed succinate dehydrogenase activity and did not correlate to high-glycogen fibers. Thus the high-glycogen fibers have an elevated enzymatic capacity for glycogen synthesis from lactate, and the pathway may involve use of the pyruvate kinase bypass enzymes.
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PMID:Glyconeogenic and glycogenic enzymes in chronically active and normal skeletal muscle. 191 41

Experimental myotonia was induced in rats by 2,4-dichloro-phenoxyacetic acid (2,4-D). After 4 to 24 h of treatment, the anterior tibialis muscles exhibited increased fatigue at low frequency (30 Hz) nerve stimulation, but they developed normal tension at high-frequency (100 Hz) stimulation. Glycogen content and the activities of glycogen phosphorylase, lactate dehydrogenase and malate dehydrogenase remained normal. The absence of correlation between fatigability and energetic metabolism in this experimental model of myotonia suggests a dysfunction in excitation-contraction coupling.
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PMID:Energetic metabolism and fatigability in experimental myotonia. 215 93

Chronic infection of woodchucks with woodchuck hepatitis virus (WHV) was associated with the development of hepatitis, foci of altered hepatocytes and hepatocellular adenomas and carcinomas. The cytomorphological and cytochemical analysis permitted the identification of three different types of focal lesions; namely, glycogen-storage foci, mixed-cell foci and intermediate-cell foci, each showing a characteristic pattern. The cells of the glycogen-storage foci had clear to acidophilic cytoplasm, and were overloaded with glycogen. They showed a marked elevation in the activity of glucose-6-phosphate dehydrogenase (G6PDH) and malate dehydrogenase (MDH), increased activity of succinate dehydrogenase (SDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glycerol-3-phosphate dehydrogenase (G3PDH), reduction in the activity of glycogen phosphorylase (PHO), glucose-6-phosphatase (G6Pase), adenosine triphosphatase (ATPase) and adenyl cyclase (ADC), and unchanged activity of glycogen synthase (SYN) and gamma-glutamyl transferase (GGT). The mixed-cell foci mainly consisted of basophilic cells poor in glycogen, but were intermingled with cells containing glycogen. These foci were characterized by a marked decrease in activity of PHO, SYN, G6Pase, G6PDH, ATPase and ADC, and increased activity of GGT, SDH, MDH and GAPDH. The intermediate-cell foci consisted of cells with both basophilic and glycogenotic cytoplasmic compartments, and showed a similar enzyme histochemical profile to the mixed-cell foci, with slight differences in the degree of elevation or reduction of some enzymes. The phenotypic similarities and the close spatial relationship between the foci of altered hepatocytes, and the hepatocellular adenomas and carcinomas in WHV-infected woodchucks, suggest that these lesions are preneoplastic. The focal morphological and metabolic aberrations emerging during hepatocarcinogenesis in WHV-infected woodchuck, are in principle similar to those identified in the course of chemical hepatocarcinogenesis in various species. The focal metabolic aberrations apparently represent a general biological response of the liver parenchyma to oncogenic agents and are closely linked to neoplastic transformation of the hepatocytes.
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PMID:Phenotypic patterns of preneoplastic and neoplastic hepatic lesions in woodchucks infected with woodchuck hepatitis virus. 215 41

The distributions of glycogen phosphorylase, hexokinase, phosphofructokinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, citrate synthase, malate dehydrogenase, beta-hydroxyacyl CoA dehydrogenase, and adenylokinase were determined in the mudpuppy retina. Distinct differences were found in regard to the glycolytic and oxidative capacities of the various layers. In the outer retina, citric acid cycle enzymes were high while glycolytic enzymes were low. Synaptic zones were distinctly enriched in all energy-producing enzymes. Mudpuppy photoreceptors were found to be rich in phosphorylase but poor in glucose-6-phosphate dehydrogenase, suggestive of some evolutionary divergence from mammals in the metabolic machinery which is used to support the visual process.
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PMID:Enzymes of energy metabolism in the mudpuppy retina. 623 83

The effect of intraperitoneal administration of cGMP (0.5 mg per animal) on carbohydrate metabolism of wound area muscle tissue was studied in experiments on rats with linear skin wounds. The content of glycogen, gluconeogenesis, activity of glycogen phosphorylase, lactate dehydrogenase and malate dehydrogenase were studied. Cyclic GMP induced a substantial activation of glycogen metabolism (elevation of gluconeogenesis, increase in the activity of glycogen phosphorylase) even the third day after the operation. The animals not given cGMP demonstrated such an activation only the fifth day following the operation. Under the effect of cGMP the activity of lactate dehydrogenase rose the third day after the operation. Thus cGMP administration to the animals with wounds leads to an earlier mobilization of energy resources thereby promoting the acceleration of wound healing.
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PMID:[Effect of cyclic guanosine monophosphate on certain indices of muscle tissue carbohydrate metabolism during the wound process]. 625 91

Individual muscle fibers from the rat anterior tibialis and soleus muscles were each analyzed in duplicate for lactate dehydrogenase (LDH, EC 1.1.1.27), malate dehydrogenase (MDH, EC 1.1.1.37), 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35), fumarate hydrotase (EC 4.2.1.2), glycogen phosphorylase (EC 2.4.1.1), 6-phosphofructokinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40), fructose-bisphosphatase (EC 3.1.3.11), and creatine kinase (EC 2.7.3.2). A few fibers were also analyzed for adenylate kinase (EC 2.7.4.3). In general, there was a wide and almost continuous spectrum of coordinated enzyme activities. In the tibialis muscle, two fiber groups could be clearly distinguished on the basis of MDH activity. The high MDH group had on the average lower LDH activity, but there was a great deal of overlap in LDH between the two groups. Less overlap was observed for phosphorylase and fructose-bisphosphatase, both inversely related to MDH. Only one main group of fibers (presumably slow twitch) was found in the soleus muscle, although enzyme activities also covered a wide range. These soleus fibers were clearly distinguished from the high MDH tibialis group by much lower activities of LDH, pyruvate kinase, and fructose-bisphosphatase.
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PMID:Enzyme levels in individual rat muscle fibers. 625 66


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