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:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Significant increase in the activity of liver succinate dehydrogenase (SDH) was observed in male Wistar rats, fed Aroclor 1260 (PCB; polychlorinated biphenyl) at 50 and 100 ppm level for 120 days. Lactate dehydrogenase (LDH) activity increased in 50 ppm PCB fed animals and decreased in 100 ppm PCB fed rats. On the other hand, enzymes like alanine and aspartate aminotransferase, alkaline and acid phosphatase showed remarkable decrease in activity in PCB fed animals. Slab gel electrophoresis of LDH isozymes showed remarkable increase in LDH2 and LDH3 and to some extent increase in LDH1 isozymes of livers of 50 ppm PCB fed animals but not in 100 ppm PCB fed groups as compared to controls. In both the PCB fed groups, liver showed centrilobular hypertrophy, hepatocellular damage, hyperplasia, karyolysis and karyorrhexis.
...
PMID:Effect of feeding polychlorinated biphenyl (Aroclor 1260) on hepatic enzymes of rats. 216 95

Mammalian and Escherichia coli succinate dehydrogenase (SDH) and E. coli fumarate reductase apparently contain an essential cysteine residue at the active site, as shown by substrate-protectable inactivation with thiol-specific reagents. Bacillus subtilis SDH was found to be resistant to this type of reagent and contains an alanine residue at the amino acid position equivalent to the only invariant cysteine in the flavoprotein subunit of E. coli succinate oxidoreductases. Substitution of this alanine, at position 252 in the flavoprotein subunit of B. subtilis SDH, by cysteine resulted in an enzyme sensitive to thiol-specific reagents and protectable by substrate. Other biochemical properties of the redesigned SDH were similar to those of the wild-type enzyme. It is concluded that the invariant cysteine in the flavoprotein of E. coli succinate oxidoreductases corresponds to the active site thiol. However, this cysteine is most likely not essential for succinate oxidation and seemingly lacks an assignable specific function. An invariant arginine in juxtaposition to Ala-252 in the flavoprotein of B. subtilis SDH, and to the invariant cysteine in the E. coli homologous enzymes, is probably essential for substrate binding.
...
PMID:New properties of Bacillus subtilis succinate dehydrogenase altered at the active site. The apparent active site thiol of succinate oxidoreductases is dispensable for succinate oxidation. 250 45

1. Mitochondrial and supernatant aspartate transaminases (EC 2.6.1.1) and supernatant alanine transaminase (EC 2.6.1.2) were purified 89-, 204- and 240-fold respectively, from dolphin muscle. Starch-gel electrophoresis of crude and purified preparations revealed that all three enzymes exist as single forms. 2. K(m) values of alpha-oxoglutarate, alanine, pyruvate and glutamate for the alanine transaminase were 0.45, 8.2, 0.87 and 15mm respectively. For the aspartate transaminases, the K(m) values of alpha-oxoglutarate, aspartate, oxalacetate and glutamate were 0.76, 0.50, 0.10 and 9.4mm respectively, for the mitochondrial form and 0.13, 2.4, 0.06 and 3.2mm respectively, for the supernatant form. 3. In all cases, as the assay pH value was decreased from pH7.3, the K(m) values of the alpha-oxo acids decreased whereas those of the amino acids increased. 4. The apparent equilibrium constants for the aspartate transaminases were independent of pH. These values were 9.2 and 6.8 for the mitochondrial and supernatant forms respectively, where [Formula: see text] 5. Studies of the inhibition of the aspartate transaminases by dicarboxylic acids indicated that these enzymes may be controlled by pools of metabolic intermediates. 6. Three key roles are suggested for the transaminases in the energy metabolism of the diving animal. First, it is believed that a combined action of the transaminases could enhance energy production during hypoxia by providing (a) fumarate from aspartate for the ATP-producing reversal of succinate dehydrogenase, and (b) alpha-oxoglutarate from glutamate for the GTP-producing succinyl thiokinase reaction. Secondly, diving mammals probably accumulate more NADH than other mammals during hypoxia. The aspartate transaminases seem particularly well suited for restoring and maintaining redox balance via the malate-aspartate cycle after aerobic metabolism is resumed. Finally, since the preferred fuel for aerobic work is fat, the combined reactions of the transaminases could be instrumental in providing increased supplies of oxaloacetate for sparking the tricarboxylic acid cycle.
...
PMID:Purification and properties of dolphin muscle aspartate and alanine transaminases and thier possible roles in the energy metabolism of diving mammals. 446 40

Some characteristics of a fumarate reductase from Streptococcus faecalis are described. The enzyme had a pH optimum of 7.4; optimal activity was observed when the ionic strength of the phosphate buffer was adjusted to 0.088. The K(m) value of the enzyme for reduced flavin mononucleotide was 2 x 10(-4)m as determined with a 26-fold preparation. In addition to fumarate, the enzyme reduced maleate and mesaconate. No succinate dehydrogenase activity was detected, but succinate did act as an inhibitor of the fumarate reductase activity. Other inhibitors were malonate, citraconate, and trans-, trans-muconate. Metal-chelating agents did not inhibit the enzyme. A limited inhibition by sulfhydryl-binding agents was observed, and the preparations were sensitive to air oxidation and storage. Glycine, alanine, histidine, and possibly lysine stimulated fumarate reductase activity in the cell-free extracts. However, growth in media supplemented with glycine did not enhance fumarate reductase activity. The enzymatic activity appears to be constitutive.
...
PMID:Fumarate reductase activity of Streptococcus faecalis. 496 Aug 92

Neurochemical consequences of repeated ethanol treatment on energy and ammonia metabolism were studied in different regions of rat brain. Energy production was decreased as indicated by lowered lactate dehydrogenase and succinate dehydrogenase activities with possible lacticacidimia. Transamination of alanine and aspartate increased while the deamination of glutamate decreased in all the regions of brain. The deamination of AMP was slightly elevated in cerebral cortex and brain stem while it was inhibited in cerebellum. Ammonia levels were persistently high, despite stepped up glutamine synthesis and ureogenesis. The synergistic action of ammonia during ethanol intoxication is envisaged.
...
PMID:Some neurochemical consequences of repeated ethanol loading in rat brain. 613 28

Hypocaloric dieting and fasting alter the contraction-relaxation characteristics of skeletal muscle and result in low frequency fatigue. We report the metabolic and structural changes in skeletal muscle in five morbidly obese female subjects who had biopsies of the gastrocnemius muscle on a base-line diet (2500 kcal/day) followed by a repeat biopsy after 2 wk of a 400-kcal/day carbohydrate diet. Hypocaloric dieting resulted in a significant increase in the intracellular muscle calcium content (p less than 0.05), which may account for the observed changes in muscle function. There were no significant changes in muscle glycogen, lactate, pyruvate, or free energy stores. There was a significant decrease in muscle enzymes [phosphofructokinase (p less than 0.05), succinate dehydrogenase (p less than 0.02)] and some muscle amino acid levels [glutamine (p less than 0.025), glycine (p less than 0.01), and alanine (p less than 0.02)], while muscle histochemistry showed type II fiber atrophy (p less than 0.025). However, these changes reflect a generalized response to hypocaloric dieting and probably do not explain the specific functional changes. Change in the muscle calcium content is probably an important mediator of the adverse functional effects of malnutrition.
...
PMID:Metabolic and structural changes in skeletal muscle during hypocaloric dieting. 620 Oct 62

The activity of certain enzymes of the energy producing metabolism of the cytoplasmic and mitochondrial compartment and of disaccharidases was determined in jejunal biopsies of 24 chronic alcoholics (CA) and 10 non-alcoholic control subjects (C). The activity of glucokinase, an enzyme of glycolysis, was markedly (44%, p less than 0.05) increased in the biopsies obtained from CA, while the activity of fructose bisphosphatase, an enzyme of gluconeogenesis, was significantly (p less than 0.05) depressed in CA when compared to C. The activity of other glycolytic enzymes was not affected in CA. The activity of L-alanine amino-transferase was lower in CA (p less than 0.05). A reduction was also seen for mean succinate dehydrogenase activity in CA (-30%), however, this difference was not statistically significant. The mean activity of lactase, maltase and sucrase was comparable in both groups.
...
PMID:Activities of cytoplasmic, mitochondrial and brush border enzymes in jejunal mucosa of chronic alcoholics. 628 1

Glycogen content and the activities of phosphorylase, phosphohexose isomerase, aldolase, glucose 6-phosphatase, succinate dehydrogenase, and alanine and aspartate amino-transferases have been biochemically determined in three gastrocnemii muscles of chick up to 9 weeks of postembryonic growth. Decline in glycogen, phosphorylase, phosphohexose isomerase and aldolase with a concomitant increase in succinate dehydrogenase reveals a switchover from glycolytic to oxidative metabolism in muscle. Activities of aminotransferases indicate the utilization of transamination products of alanine and aspartate in oxidative pathway. Transiently increased glucose 6-phosphatase seems to restrict glycogenolytic and glycolytic metabolism and thereby pave way for the acceleration of oxidative metabolism in developing muscle.
...
PMID:Does glucose 6-phosphatase regulate metabolic transformation in developing skeletal muscle? 633 26

Chronic sumithion toxicity in experimental crabs was induced by exposing them for 15 and 30 days to 0.04 ppm sumithion solution. The enzymes concerned with glycogenolytic metabolism (phosphorylase), glycolytic metabolism (aldolase), aerobic metabolism [succinate dehydrogenase (SDH), malate dehydrogenase (MDH)], anaerobic metabolism, lactate dehydrogenase (LDH) and alanine amino transaminase (AIAT)], were assayed in the muscle of control and experimental crabs. Glycogen, pyruvic acid, lactic acid were also estimated in the muscle of both control and experimental crabs. The muscle tissue of chronic sumithion-exposed crab exhibited suppressed glycogenolysis and glycolysis with an onset of gluconeogenesis. In general, chronic sumithion exposure seems to result in an elevation of the synthetic phase of muscle carbohydrate metabolism.
...
PMID:Chronic sumithion toxicity: effect on carbohydrate metabolism in crab muscle. 682 35

1. The factors affecting the pathway of glutamate oxidation were studied in isolated rat-liver mitochondria in incubations of 2-3 min. 2. It was found that bicarbonate at a physiological concentration has a profound effect on the pathway of glutamate oxidation. Ammonia formation via glutamate dehydrogenase is stimulated by bicarbonate [from 5.48 +/- 0.29 (n = 10) to 9.57 +/- 0.73 (n = 8) nmol X min-1 X mg protein-1], whereas aspartate formation via the transamination pathway is inhibited [from 38.41 +/- 2.24 (n = 9) to 24.56 +/- 3.28 (n = 6) nmol X min-1 X mg protein-1]. 3. Bicarbonate has no effect on the rate of transport of glutamate via the glutamate-hydroxyl translocator. 4. The interaction of bicarbonate with the pathway of glutamate oxidation occurs primarily at the level of succinate dehydrogenase, due to competitive inhibition of the enzyme by bicarbonate. 5. Inhibition by bicarbonate of the transamination pathway leads to a decrease in intramitochondrial 2-oxoglutarate, so that the deamination pathway is stimulated. 6. Using an equation which describes flux through glutamate dehydrogenase kinetically, it could be shown that the bicarbonate-induced decrease in intramitochondrial 2-oxoglutarate quantitatively accounts for the enhanced rate of deamination. 7. It is concluded that in the intact liver flux through glutamate dehydrogenase is sufficient to account for the ammonia formation required for urea synthesis from substrates such as alanine.
...
PMID:Bicarbonate and the pathway of glutamate oxidation in isolated rat-liver mitochondria. 685 31


<< Previous 1 2 3 4 5 6 7 Next >>

---