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:1.8.1.4 (diaphorase)
2,754 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukocytes, approached by histoenzymological methods for demonstration of dihydrofolate dehydrogenase, NADH2-diaphorase, lactate dehydrogenase and alcaline phosphatase activities, provided information about the impaired metabolic balance of thyrotoxicosis, Cushing and Addison diseases. The most relevant variations were found in thyrotoxicosis, the most sensitive enzyme was dihydrofolate dehydrogenase and the less sensitive was alcaline phosphatase. The neutrophils and lymphocytes had more evident enzymic variations.
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PMID:Cytoenzymologic activities of some oxidroeductases and alkaline phosphatase of leucocytes in Basedow, Cushing and Addison diseases. 81 Oct 42

The authors investigated the dehydrogenase histochemistry of arterioles on 22 muscular biopsies from 14 male and 8 female patients with different clinical forms of atherosclerosis, and in 5 controls. There was a diminution with age of all the enzymes studied. In 3 of 6 cases with pathological lesions (thickening of endothelium, fragmentation of the internal elastic lamina, thrombosis) there was a regional diminution of NADH-diaphorase and NADPH-diaphorase activities parallel with an increase of the reaction for lactic dehydrogenase and glutamate dehydrogenase in the muscular cells and endothelium.
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PMID:Histoenzymology of muscular arterioles. 81 50

Microorganisms formed readily ethylenethiourea (ETU) from 5,6-dihydro-3H-imidazo[2,1-c]-1,2,4-dithiazole-3-thione (DIDT), a spontaneous decomposition product of ethylenebisdithiocarbamates. This conversion also takes place after addition of reducing compounds like cysteine, glutathione or ascorbic acid. It consists of two steps: reduction of the S-S bond of DIDT with subsequent release of CS2 to form ETU. DIDT was reduced by NADH in the presence of enzyme extracts from Pseudomonas fluorescens or Asperigillus niger, or by commercial glutathione reductase or lipoamide dehydrogenase. ETU was formed as a result of this enzymatic reduction. The flavin compounds FMN and FAD were also able to promote the reduction of DIDT by NADH.
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PMID:Formation of ethylenethiourea from 5,6-dihydro-3H-imidazo[2,1-c]-1,2,4-dithiazole-3-thione by microorganisms and reducing agents. 81 82

The fungicide dexon (p-dimethylaminobenzenediazosulfonate, Na-salt) inhibits the NADH oxidase activity of submitochondrial particles (ETP) from beef heart (semi-inhibition concentration 1.4 muM), while the succinate oxidase activity is unaffected. Measurements of the activity of several enzymatic partial reactions of the respiratory chain of ETP suggest that dexon acts directly on the flavine of NADH dehydrogenase. Soluble NADH-cytochrome c-oxidoreductase (MAHLER) and rotenone-insensitive NADH ubiquinone reductase are also inhibited by dexon. At low concentrations of dexon, inhibition of ETP starts slowly only after addition of NADH. Preincubation without NADH increases the amount of inhibition, but does not prevent the time delay. It is assumed that an electron flux through the respiratory chain, or reduction of flavine is prerequisite for the reaction of dexon with the action site. Furthermore, dexon inhibits the NADH dehydrogenase located at the outer surface of the inner membrane of plant mitochondria, accessible to extramitochondrial NADH and insensitive to rotenone, as has been shown on isolated mitochondria from cauliflower (Brassica oleracea L). In addition, dexon inhibits selectively the NADH dehydrogenase of the DT diaphorase (ERNSTER) from rat liver cytosol. In contrast, the dicoumarol-insensitive NADH dehydrogenase (ZINSMEYER et al.) from rat liver cytosol, the NADH-cytochrome b5-reductase (STRITTMATTER) from rat liver microsomes, the rotenone-insensitive NADH-cytochrome c-oxidoreductase of the outer membrane of rat liver mitochondria, soluble NADH-oxidase from Escherichia coli, and NADH-dehydrogenase from human erythrocytes are not inhibited. The results suggest that dexon is a group reagent to certain pyridine nucleotide-dependent flavine enzymes.
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PMID:[Action of the systemic fungicide dexon on several NADH dehydrogenases]. 82 48

The use of a low pressure perfusion method for enzyme histochemical reactions in the cochlea of guinea pig is proved in the case of the demonstration of the NADH-diaphorase. It was shown by measuring of the microphonic potentials during the perfusion, that the perfusion medias caused practically no chemical or mechanical defections of the hair cells under the new conditions of working. The activities of the NADH-diaphorase were demonstrated mainly in the hair cells and in the nervous fibres of the organ of Corti. A remarkable NADH-diaphorase activity was detected in the Boettcher cells too.
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PMID:[A low pressure perfusion method suitable for enzyme histochemical studies on the cochlea exemplified with the demonstration of NADH-diaphorase activity (author's transl)]. 82 79

In order to localize 3beta-hydroxysteriod dehydrogenase activity on the ultrastructural level, sections of Newt and Rat adrenocortical tissues, fixed in a mixture of glutaraldehyde (0.25%) and formaldehyde (1%), were incubated in a medium containing namely a 3beta-hydroxysteroid as substrate, NAD, potassium ferricyanide as final electron acceptor and copper sulfate. In some experiments, phenazine methosulfate (PMS), an electron carrier which can substitute for the activity of the endogenous NADH-diaphorase, is added at various concentrations to the incubation medium. A final precipitate of copper ferrocyanide is observed in the immediate vicinity of the tubules of the smooth endoplasmic reticulum, or in contact with their external faces. The reaction product can also be seen in mitochondrial cristae. The reaction does not take place in incubation media lacking substrate or containing cyanoketone, a specific inhibitor of 3beta-hydroxysteroid dehydrogenase. the addition of PMS to the incubation medium increases the intensity of the reaction, but does not modify the localization of the precipitate.
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PMID:Ultracytochemical demonstration and probable localization of 3beta-hydroxysteroid dehydrogenase activity with a ferricyanide technique. 83 7

Methyl-GAG was tested in organotypic cultures of malignant tumors of human and mice. In 3 cases, a reduction of the activity of two oxydoreductases (lactate dehydrogenase and NADH-diaphorase) after treatment with methyl-GAG was observed whereas in 19 other cultivated tumors no change of enzyme activity was induced by methyl-GAG. Electronmicroscopy revealed only minor structural alterations of tumor cells after application of methyl-GAG as compared with control cultures.
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PMID:[Histochemical and ultrastructural investigations on the activity of methylglyoxal (bis)-guanylhydrozan (methyl-GAG) on organ cultures of malignant tumors (author's transl)]. 86 71

1. The effect of guanidine hydrochloride (GuHCl) on pig heart lipoamide dehydrogenase [NADH: lipoamide oxidoreductase, EC 1.6.4.3.] was investigated by means of enzymatic activity and optical measurements (CD, absorption, and fluorescence spectra). The activity of the enzyme decreased on increasing the concentration of GuHCl and the enzyme was completely inactivated in 2.0 M GuHCl. 2. The contents of alpha-helix, beta, and unordered forms in lipoamide dehydrogenase were estimated to be 34, 14, and 52%, respectively. On increasing the concentration of GuHCl, the content of alpha-helix in lipoamide dehydrogenase decreased, whereas the content of the beta form hardly changed. 3. The native lipoamide dehydrogenase showed absorption, CD, and fluorescence spectra characteristic of bound FAD in the visible region, suggesting hydrophobic interaction between the protein moiety and FAD chromophore. The absorption, CD, and fluorescence spectra of the enzyme in 2.0 M GuHCl were similar to those of free FAD in the buffer, suggesting the release of FAD from the protein moiety. 4. The protein fluorescence spectrum of lipoamide dehydrogenase had a maximum at 350 nm blue-shifted by 8 nm from that of tryptophan in aqueous solution. The maximum of the enzyme in 2.0 M GuHCl was red-shifted to 357 nm. This suggests exposure of tryptophan residues to a polar environment. The maximum, 352nm, of the apoenzyme shifted to 350 nm on addition of FAD. These results show that the conformation in the microenvironment of some tryptophan residues in lipoamide dehydrogenase is affected by the dissociation-association of FAD. 5. The contents of alpha-helix, beta, and unordered forms in the apoenzyme were estimated to be 35, 8, and 57%, respectively. These values are similar to those of the native holoenzyme. The alpha-helical structure in the apoenzyme molecule was more sensitive to GuHCl than that in the holoenzyme. FAD and two hydrophobic probes, 8-anilinonaphthalene-1-sulfonate (ANS) and 4 benzolamido-4'-aminostilbene-2,2'-disulfonate (MBAS), which can bind to the apoenzyme, stabilized the alpha-helical structure in the apoenzyme molecule.
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PMID:Effect of guanidine hydrochloride on the holo- and apo-enzymes of pig heart lipoamide dehydrogenase. 93 80

Sheep erythrocyte membranes have been shown in this laboratory to undergo spontaneous vesiculation when incubated at 4 degrees, fractionating into two bands in dextran gradients (R. McGuire and R. Barber, submitted for publication). While vesicles were observed to be formed in several solvent systems, incubation in the presence of complexors to remove divalent cations was found to be the most efficient method for both vesicle formation and their detachment from the residual membrane. We report here on the characterization of these vesicles formed by spontaneous vesiculation. In the presence of a hypotnoic buffer containing 1 mM EDTA, vesicle production proceeds linearly up to 50 hours and declines, reaching its maximum at 72 hours with up to 20% of the total membrane protein found in the upper band. This upper band is shown in electron micrographs to be composed chiefly of closed vesicles, while the particles in the lower band appear morphologically similar to the original ghosts. Total phospholipid phosphorus and cholesterol in the vesicles are enriched to the same extent, giving a lipid to protein ratio of 2 times that found for whole ghosts. The vesicles contain the same individual phospholipids as the ghosts. The protein composition of these vesicles is unique, in that they are almost depleted in the known extrinsic membrane proteins, while containing practically all types of the various glycoproteins of the original membrane. The two main intrinsic membrane proteins (with apparent molecular weights of 160,000 and 100,000) are found almost exclusively in the vesicles, virtually depleted in the residual ghost-like particles. The protein with 160,000 molecular weight is shown here to be a glycoprotein, giving an anomalous molecular weight on sodium dodecyl sulfate gels and having a molecular weight of approximately 50,000 after lipid extraction. This same glycoprotein appears to fractionate with acetylcholinesterase. From the accessibilities of the substrates to the membrane acetylcholinesterase and NADH-diaphorase, it is concluded that the vesicles are right-side-out and sealed to small molecules. There are more membrane sialic acid residues accessible to neuraminidase in the vesicles (in terms of number of residues/mg og membrane protein) than in ghosts, further supporting the conclustion that these vesicles have a normal orientation and are enriched in glycoproteins. The specific activity of acetylcholinesterase in the vesicles is increased 5- to 6-fold over that found in the original ghosts and almost 20-fold over that in the residual ghost-like particles. Consequently, spontaneous vesiculation occurs simultaneously with the enrichement of specific membrane proteins in certain regions of the lipid bilayer. It is postulated that these domains in the membrane, containing clusters of specific intrinsic membrane proteins, bud out and subsequently release glycoprotein-enriched lipid vesicles.
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PMID:Glycoprotein-enriched vesicles from sheep erythrocyte ghosts obtained by spontaneous vesiculation. 93 96

The interaction of hydrophobic probes, 8-anilinonaphthalene-1-sulfonate (ANS) and 4-benzoylamido-4'-aminostilbene-2, 2'-disulfonate (MBAS), with pig heart lipoamide dehydrogenase [NADH: lipoamide oxidoreductase, EC 1.6.4.3] was investigated. When ANS or MBAS was mixed with the apoenzyme of lipoamide dehydrogenase, the fluorescence quantum yield, of each dye was enhancedd markedly and the emission maxima concurrently shifted to the blue. The quantum yield, 0.038, of ANS bound to the apoenzyme, calculated from the corrected emission spectrum, was eight times higher than that in buffer solution, and the value, 0.0090, for bound MBAS was eighteen times higher than that in buffer solution. Moreover, the absortion bands of both ANS and MBAS shifted to the red upon binding with the apoenzyme. A general feature of the absorption spectra of these dyes observed on changing the solvent from polar to apolar was a red shift of the absorption bands. These results indicate that ANS or MBAS bound to the apoenzyme of lipoamide dehydrogenase is situated in a hydrophobic region of the apoenzyme molecule. It was found that 2 moles of each dye was bound per mole of the apoenzyme, which contains two polypeptide chains. The dissociation constants for the ANS- and MBAS-apoenzyme complexes were estimated to be 1.03X10(-5) and 1.54X10(-5) M, respectively. The enhanced fluorescence of both dyes bound to the apoenzyme decreased linearly upon adding FAD and disappeared at about 2 moles of FAD per mole of the apoenzyme. This suggests that both ANS and MBAS were displaced from their binding sites on the apoenzyme by FAD. The protein fluorescence spectrum of the apoenzyme had a maximum at 352 nm, which was blue-shifted by 6 nm from that of tryptophan in the buffer. Upon binding ANS or MBAS, the maximum of the protein fluorescence of the apoenzyme returned to 350 nm for the holoenzyme, and the fluorescence intensity decreased. Thus, the conformation around some tryptophan residues was affected by the binding of the dyes. When guanidine hydrochloride (GuHCl) was added to the ANS-apoenzyme complex solution, the enhanced fluorescence due to the bound ANS decreased and the emission maximum concurrently shifted to the red. Further, the maximum of the protein fluorescence of the apoenzyme shifted to the red, indicating the exposure of some tryptophan residues buried in an apolar region of the apoenzyme. Thus the binding of ANS to the apoenzyme was inhibited by protein denaturation due to GuHCL. In contrast, the holoenzyme of lipoamide dehydrogenase did not bind ANS or MBAS at all.
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PMID:Interaction of hydrophobic probes with the apoenzyme of pig heart lipoamide dehydrogenase. 95 45


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