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Query: EC:1.1.1.41 (
isocitrate dehydrogenase
)
3,101
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Placental aldose reductase (EC 1.1.1.21) was incubated with glucose in the presence of [4A-2H] NADPH prepared in the oxidation of [2-2H] isocitrate by
isocitrate dehydrogenase
(EC 1.1.1.42) or [4B-2H] NADPH prepared in the oxidation of [1-2H]
glucose-6-phosphate dehydrogenase
(EC 1.1.1.49). The sorbitol formed from [4A-2H] NADPH contained deuterium and from [4B-2H] NADPH it did not. Therefore, aldose reductase in an A-type enzyme.
...
PMID:Stereospecificity of the hydrogen transfer catalyzed by human placental aldose reductase. 1 22
Alkylation at N-1 of the NADP+ adenine ring with 3,4-epoxybutanoic acid gave 1-(2-hydroxy-3-carboxypropyl)-NADP+. Enzymic reduction of the latter, followed by alkaline Dimroth rearrangement and enzymic reoxidation, gave N6-(2-hydroxy-3-carboxypropyl)-NADP+. On the other hand, bromination at C-8 of the NADP+ adenine ring, followed by reaction with the disodium salt of 3-mercaptroproionic acid, gave 8-(2-carboxyethylthio)-NADP+. Carbodimide coupling of the three carboxylic NADP+ derivatives to polyethyleneimine afforded the corresponding macromolecular NADP+ analogues. The carboxylic and the polyethyleneimine derivatives synthesized have been shown to be co-enzymically active with yeast
glucose-6-phosphate dehydrogenase
, liver glutamate dehydrogenase and yeast aldehyde dehydrogenase. The degree of efficiency relative to NADP+ with the three enzymes ranged from 17% to 100% for the carboxylic derivatives and from 1% to 36% for the polyethyleneimine analogues. On comparing the efficiences with the three enzymes of the N-1 derivatives to the one of the corresponding N6 anc C-8 analogues, the order of activity was N-1 greater than N6 greater C-8, except in the case of the carboxylic compounds with glutamate dehydrogenase, where this order was inverted. None of these modified cofactors were active with pig heart
isocitrate dehydrogenase
.
...
PMID:Preparation of coenzymic activity of soluble polyethyleneimine-bound NADP+ derivatives. 1 99
Coho salmon (Oncorhynchus kisutch), 8 to 18 months of age, were maintained in culture tanks and were fed three semipurified diets. The diets contained 40% of energy from protein and 11.5%, 23%, or 46% of energy from lipid. The body weight gain and food conversion factors were similar among groups of fish fed the diets in each of the three experiments. Wet weight of mesenteric adipose tissue increased with increased amount of lipid in the diet; however, epaxial muscle lipid content was not influenced by the lipid content of the diet. Several hepatic and adipose tissue lipogenic enzymes (fatty acid synthetase, citrate cleavage enzyme, malic enzyme,
glucose-6-phosphate dehydrogenase
, 6-phosphogluconate dehydrogenase, and NADP-
isocitrate dehydrogenase
) were assayed. These lipogenic enzymes exhibited high activities in liver and relatively low concentration in adipose tissue of the fish. The activities of all the hepatic lipogenic enzymes assayed, except for NADP-
isocitrate dehydrogenase
, were depressed as the level of lipid in the diet was increased; however, the activities of these enzymes in mesenteric adipose tissue were not influenced by the diets fed. The results of this study indicate that dietary lipid depresses hepatic lipogenic enzyme activities and that the liver may be a more important site for fatty acid synthesis than is adipose tissue in coho salmon.
...
PMID:Influence of dietary lipid on lipogenic enzyme activities in coho salmon, Oncorhynchus kisutch (Walbaum). 1 2
At present soluble NADP-dependent dehydrogenases are histochemically demonstrated in three different ways: according to the standard method incubation in aqueous media leads to the precipitation of formazan, the formation of which depends entirely on the presence of endogeneous NADPH2-tetrazolium reductases. With the two more recently established methods these reductases are by-passed with the use of intermediate electron acceptors incorporated in the medium. In addition, enzyme diffusion is inhibited either by an increased viscosity of the medium (PVA) or by a semipermeable membrane separating the medium from the section. Depending on the technique applied different distribution patterns have been described. By altering the concentrations of substrates, coenzyme, tetrazolium salt and cytochrome oxidase inhibitor, it was possible to improve both the PVA and membrane methods. Although similar results were obtained, because of its advantages the PVA method is recommended in this report and a detailed description is given. Using the latter for the demonstration of
glucose-6-phosphate dehydrogenase
(
G6PDH
), 6-phosphogluconate dehydrogenase (6PGDH), malic enzyme (ME) and
isocitrate dehydrogenase
(ICDH), characteristic distribution patterns were obtained in the liver parenchyma of male and female rats. For the first time a high
G6PDH
activity could be demonstrated in nonparenchymal cells which are mainly found in zone 1 of the liver acinus.
...
PMID:NADP-dependent dehydrogenases in rat liver parenchyma. I. Methodological studies on the qualitative histochemistry of G6PDH, 6PGDH, malic enzyme and ICDH. 2 20
Impaired testosterone biosynthesis in Leydig cells from streptozotocin treated rats is correlated with the reduced activity of
glucose-6-phosphate dehydrogenase
, 6-phosphogluconate dehydrogenase and
isocitrate dehydrogenase
. The results shown demonstrate that in the diabetic state the activity of these enzymes is reduced by almost 50 to 59% from normal levels. Insulin treatment restored their activities to normal levels. The diminished supply of NADPH in diabetic interstitial tissue is not the unique factor in the control of steroidogenesis, since the availability of large amounts of exogenous NADPH in the incubations of Leydig cell did not reduce the differences in testosterone synthesis observed when compared with normal cells.
...
PMID:NADPH generating enzymes in Leydig cells from diabetic rats. 3 55
The energy metabolism of cardiac hypertrophy in spontaneously hypertensive rats (SHR) was studied chronologically by histochemical and in part chemical methods. The activities of various enzymes, such as
glucose-6-phosphate dehydrogenase
(
G6PDH
), lactate dehydrogenase (LDH),
isocitrate dehydrogenase
, succinate dehydrogenase, beta-hydroxybutylate dehydrogenase (beta-HBDH) and monoamine oxidase (MAO) in the cardiac muscle were determined histochemically. beta-HBDH activity was greatly increased in the stage of developing hypertension in SHR. LDH activity increased simultaneously with the rise of beta-HBDH activity. Moreover, MAO activity increased markedly in later stages when the blood pressure was already elevated in SHR. To confirm the histochemical findings of beta-HBDH activity, the mitochondrial fraction of cardiac muscle was subjected to chemical assay. The chemical findings of myocardial beta-HBDH in SHR corresponded well with the histochemical findings. The myocardial beta-HBDH activity in SHR increased markedly at the age of 5 to 9 weeks, while no or minimal activity was found in controls of the same age. No significant difference of beta-HBDH activity was observed between SHR and controls in the mitochondrial fraction from the diaphragm and liver. The increase of beta-HBDH activity in the cardiac muscle of SHR prior to the development of cardiac hypertrophy suggests that the metabolism of ketone bodies may play an important role in providing the energy necessary for the development of cardiac hypertrophy in SHR.
...
PMID:Cardiac hypertrophy in spontaneously hypertensive rats. 12 86
In this study, it was observed that Cd administration had effects on metal distribution and enzyme activities and induced metallothionein in the soluble fraction of the duodenal mucosa. Wistar rats were given water containing 100 ppm of Cd ad libitum for 30 days. Cd treatment caused a significant increase in the mucosal weight and in the soluble protein. The existence of metallothionein was apparent and 40% of the soluble Cd was bound to the thionein. Most of the remaining Cd was bound to the larger proteins. The activities of
isocitrate dehydrogenase
(ICDH) and
glucose-6-phosphate dehydrogenase
(
G6PDH
) enzymes, localized in the soluble fraction, were significantly increased by Cd ingestion. The increase of Zn and the decrease of Mn and Mg were also observed in the soluble fraction of the duodenal mucosa.
...
PMID:The effect of cadmium on soluble proteins, enzymes, and essential metals of the duodenal mucosa. 14 14
The activity of the enzymes of the citric acid cycle, glycolysis, and hexose monophosphate pathway was studied during germination of the spores of Bacillus anthracoides and upon their treatment with calcium hypochlorite. No activity of
isocitrate dehydrogenase
and
glucose-6-phosphate dehydrogenase
was found in the extracts of the vegetative cells, contrary to the spores and initiated spores. The activity of other enzymes changes but slightly in the course of germination of the spores. Treatment of the spores with calcium hypochlorite inhibited their initiation and germination and the activity of several enzymes, especially malate dehydrogenase,
isocitrate dehydrogenase
, and fumarase.
...
PMID:[Change in the activity of the enzymatic systems of Bacillus anthracoides spores during germination and under the action of Ca hypochlorite]. 17 77
The effects of two environmental temperatures (T; 16 degrees and 31 degrees), five diet dilutions (D; 0%, 12.5%, 25%, 37.5% and 50%), and five daily treadmill running periods (E; 10 minutes, 40 minutes, 70 minutes, 100 minutes, and 130 minutes) upon enzyme activities of liver and adipose tissue of male rats were observed. Liver enzymes studied were glucose-6-phosphatase (G6Pase), 6-P-gluconate dehydrogenase (6PGD),
glucose-6-phosphate dehydrogenase
(
G6PD
), fructose diphosphatase (FDPase), NADP-
isocitrate dehydrogenase
(ICDH), and malic enzyme (ME). Adipose tissue (epididymal fat) enzymes (6PGD,
G6PD
, and ME) were studied as well as the in vitro incorporation of the 14C of [U-14C] glucose into liberated 14CO2 and into the triglycerides, free fatty acids, and total lipids by adipose tissue slices. Equations describing regression surfaces for these responses (expressed as units/100 g body weight) could contain significant linear coefficients of the independent variables (T, D, and E), their first order interactions, and quadratic coefficients for D and E. Significnat regression coefficients for activities of liver enzymes associated with increased lipogenesis (6PGD,
G6PD
, and ME) produced response surfaces with conformations generally concave downward. All enzymes possessed positive and negative linear and quadratic coefficients for D which caused response surfaces to be concave downward with respect to that variable. Also, 6PGD and
G6PD
(positive linear and negative quadratic coefficients for E) exhibited response surfaces concave downward with respect to E. Additionally, 6PGD showed greater activity at 31 degrees than at 16 degrees while
G6PD
showed no effect of temperature on activity. Liver ICDH, probably important in supplying reducing equivalents for fatty acid synthesis, evidenced response surfaces almost identical to those for 6PGD. Significant regression coefficients for activity of liver enzymes associated with increased gluconeogenesis (FDPase and G6Pase) produced for FDPase a response surface concave downward with respect to both D and E with greater values at 31 degrees than at 16 degrees; but for G6Pase non-concave surfaces with lesser values at 31 degrees than at 16 degrees. Significant regression coefficients for activities of adipose enzymes associated with increased lipogenesis produced for 6PGD a response surface concave upward due to negative linear and positive quadratic coefficients for both D and E. For
G6PD
and ME regression surfaces were concave upward with respect to E, but these were modified by positive and negative linear coefficients, respectively, for D. Significant regression coefficients for incorporation of the 14C of glucose into triglycerides and free fatty acids of adipose tissue slices and their production of 14CO2 yielded response surfaces concave upward with respect to E (negative linear and positive quadratic coefficients). In addition, the surface for free fatty acids was concave upward with respect to D. The 14CO2 production was greater at 16 degrees than at 31 degrees...
...
PMID:Effects in the rat of environmental temperature, diet dilution, and treadmill running on liver and adipose enzymes and metabolism of 14C-glucose: a multiple regression analysis. 18 37
Oxidoreductases were studied histochemically in 162 cases of neuroectodermal tumors. In order of decreasing activity in the cytoplasma these enzymes could be arranged as follows: NADH diaphorase, lactate dehydrogenase, NADPH diaphorase, glutamate dehydrogenase,
glucose-6-phosphate dehydrogenase
,
isocitrate dehydrogenase
, succinate dehydrogenase, malate dehydrogenase. The weak activity of Krebs cycle enzymes and the relatively strong activity of other oxidoreductases, particularly of lactate dehydrogenase, permits to conclude that glycolysis prevails over oxidative processes in neuroectodermal tumor cells. But this should not be interpreted as a decrease of the Krebs cycle enzymes in astrocytoma and oligodendroglioma cells as compared with their parent cells because the latter themselves display a weak activity of these enzymes. A real decrease of Krebs cycle enzyme activity was established only for tumors, the parent cells of which are characterized by a strong (in choroid-papillomas) or moderate (in ependymomas) activity of these enzymes. Many neuroectodermal tumors, in particular those of astrocytic origin, demonstrate a certain correlation between the amount of cytoplasm and oxidoreductase activity. This results in enzymatic polymorphism of the tumor tissue. A certain similarity was established of the oxidoreductase activity in tumor cells and in reactive hypertophic astrocytes. This indicates that both tumor cells and reactive astrocytes may in certain conditions utilize similar mechanisms of increased metabolism. The oxidoreductase activity correlates not with the grade of anaplasia but with different directions of anaplasia reflected in different variants of neuroectodermal tumors. The concept "anaplasia" includes not only certain degrees of dedifferentiation of tumor cells but, as it has been shown histochemically, also an increase of metabolic processes in the tumor cell cytoplasma.
...
PMID:Histochemistry of oxidoreductases, enzymatic polymorphism and anaplasia of neuroectodermal tumors. 18 68
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