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)

Under study were activities of glycolysis enzymes: LDH, Krebs' cycle--SDH, those of electron transport system--NAD and NADP-diaphorase, and of the hydrolytic enzymes, acid and alkaline phosphatases in the hypothalamus, as were morphofunctional shifts in these enzymes' activities in poisoning with organophosphorus compounds. The experiments were carried out in 72 white male outbred rats weighing 180-200 g, that were administered PHOS antio (an organo-phosphorus compound) in a daily dose of 0.1 LD50 for 30 days. Early dates of poisoning were associated with an essential rise of the redox enzymes and a lowering of the hydrolytic enzymes levels, this being paralleled by morphologic signs of activation of the neurosecretory cells. Later high levels of neurosecretory material in the neurosecretory nuclei and reduced counts of neurosecretory cells were coupled with almost all the enzymes' activities lowering. This permits a conclusion that changed activities of the enzymic systems may be one of the pathogenetic mechanisms and possible causes of neurosecretory cell dysfunction in pesticide poisonings.
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PMID:[The enzymatic activity of the neurosecretory nuclei of the anterior hypothalamus in exposure of the body to organophosphorus compounds]. 801 55

It has been shown that morphogenesis of Leishmania major in each culture passage is characterised by the depletion of RNA and increase in its dispersion degree, by the change of the NADP-H-diaphorese, peroxidase and Janus green-B-oxidative activity in the promastigotes. Cytochemical peculiarities of invasive metacyclic promastigotes are an extreme depletion of RNA, its disperse form, a low activity of oxidative enzymes. This properties may manifest the pre-adaptation of Leishmania promastigotes to the development in vertebrate host. In the process of long-term cultivation of L. major the virulence, the metacyclogenesis, and the level of NADF-H-diaphorase and peroxidase activity decrease from passage to passage, but the ability to oxidate the Janus green-B increases.
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PMID:[The virulence and cytochemical properties of Leishmania major during long-term cultivation]. 832 58

It has been shown that an increase of virulence of Leishmania major, L. tropica, L. braziliensis as a result of passing through animals and its decrease during the cultivation are accompanied by certain changes of biochemical characteristics of these promastigotes. In the former case the activity of NADP-H-diaphorase and peroxidase of promastigotes and their ability to be transformed into final (invasional) metacyclic forms increase and in the latter case these characteristics decrease. The level and duration of virulence in culture depend not only on absolute value of the above-mentioned characteristics but also on the graduality of their change. Metacyclogenesis and activity of oxidative enzymes are suggested to be the correlates of virulence of various Leishmania species.
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PMID:[The virulence, metacyclogenesis and respiratory enzymes of Leishmania isolated in culture from laboratory animals]. 841 49

Systematic replacement of a set of amino acids in the beta alpha beta-fold of the NAD-binding domain of Escherichia coli dihydrolipoamide dehydrogenase has been used to convert its coenzyme specificity from NAD to NADP. After comparison with the homologous enzyme glutathione reductase, Glu 203 was replaced with a valine residue, thereby eliminating the potential to form hydrogen bonds with the 2'- and 3'-OH groups of the adenine ribose in NAD. Similarly, Met 204, Pro 210, Phe 205, and Asp 206 were replaced by an arginine, an arginine, a lysine, and a histidine residue, respectively, to provide a nest of positive charge to accommodate the 2'-phosphate group of the incoming NADP. In addition, Gly 185 and Gly 189 in the beta alpha beta motif were replaced with alanine residues to facilitate the positioning of the newly introduced Val 203 by allowing a flip of the peptide bond between residues Gly 180 and Gly 181. Wild-type dihydrolipoamide dehydrogenase is inactive with NADP, but the mutant enzyme displayed high levels of activity with this coenzyme, the values of Km, kcat, and kcat/Km comparing favorably with those found for the wild-type enzyme operating with NAD. The mutant enzyme was also capable of assembly in vitro to form an active pyruvate dehydrogenase multienzyme complex, the coenzyme specificity of which reflected that of its dihydrolipoamide dehydrogenase component. These experiments should make it possible now to study the effects in vivo of requiring a crucial catabolic enzyme to function with the wrong coenzyme, an important extension of protein engineering into the living cell.
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PMID:Creation of an NADP-dependent pyruvate dehydrogenase multienzyme complex by protein engineering. 845 41

Thioredoxin reductase from Escherichia coli is a member of the pyridine nucleotide-disulfide oxidoreductase family, and contains one FAD and one redox-active disulfide per subunit. It is known that two other well-studied members of this family, lipoamide dehydrogenase and glutathione reductase, cycle between the two electron-reduced and fully oxidized forms in catalysis. Enzyme-monitored turnover shows that the spectrum of thioredoxin reductase during turnover represents fully reduced flavin with NADP(H) bound. Whether the pyridine nucleotide bound is NADPH or NADP+ is dependent on the concentration of each species, i.e., how far turnover has progressed. It is also shown that the midpoint potentials of this enzyme are increased through the differential binding of NADP+ to the oxidized and reduced form of the enzyme. When combined with other kinetic and oxidation/reduction studies of this enzyme, these results indicate that thioredoxin reductase cycles between the four-electron-reduced and two-electron-reduced forms in catalysis, and that it does so with pyridine nucleotide bound. These results clarify the mechanism of thioredoxin reductase in relation to the known structure the enzyme, and provide support for earlier work in which we proposed that this enzyme utilizes a ternary complex mechanism in catalysis.
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PMID:Enzyme-monitored turnover of Escherichia coli thioredoxin reductase: insights for catalysis. 866 60

The acoD gene, which encodes a dihydrolipoamide dehydrogenase component of the acetoin dehydrogenase enzyme system of Klebsiella pneumoniae was isolated and the nucleotide sequence determined. The gene is capable of encoding a protein of 465 amino acid residues with conserved binding domains for NAD and FAD, and two redox-active cysteine residues. The acoD gene product exhibited a Michaelis constant of 170 microM for NAD, while NADP can not be used as a substrate. The purified enzyme appeared to be a dimer of the acoD gene product. It did not associate tightly with the E1 and E2 components of either acetoin dehydrogenase or 2-oxoglutarate dehydrogenase to form an active multi-enzyme complex.
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PMID:Identification and characterization of the acoD gene encoding a dihydrolipoamide dehydrogenase of the Klebsiella pneumoniae acetoin dehydrogenase system. 882 47

The petH genes encoding ferredoxin:NADP+ reductase (FNR) from two Anabaena species (PCC 7119 and ATCC 29413) were cloned and overexpressed in E. coli. Several positively charged residues (Arg, Lys) have been implicated to be involved in ferredoxin binding and electron transfer by cross-linking, chemical modification and protection experiments, and crystallographic studies. The following substitutions were introduced by site-directed mutagenesis: R153Q, K209Q, K212Q, R214Q, K275N, K430Q and K431Q in Anabaena 29413 FNR, and R153E, K209E, K212E, R214E, K275E, R401E, K427E, and K431E in Anabaena 7119 FNR. Comparison of the diaphorase activities, the specific rates of ferredoxin dependent NADP(+)-photoreduction and cytochrome c reduction catalyzed by FNR showed that all these amino acid residues were required for efficient electron transfer between FNR and ferredoxin. Replacement of any one of these basic residues produced a much more pronounced effect on the cytochrome c reductase activity, where FNR, reduced by NADPH, acted as electron donor, than in the reduction of NADP+ by photosystem I via FNR. A mutation involving the replacement of positive charge by a neutral amide produced in all cases a smaller inhibitory effect on the activity than a charge reversal mutation. In addition, it has been found that R214 was necessary for stable integration of the non covalently bound FAD-cofactor.
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PMID:Interaction of positively charged amino acid residues of recombinant, cyanobacterial ferredoxin:NADP+ reductase with ferredoxin probed by site directed mutagenesis. 951 8

The Escherichia coli flavohaemoglobin (Hmp) has a globin-like N-terminal domain and a ferredoxin-NADP-reductase-like C-terminal domain. We show here that purified Hmp oxidises both NADH and NADPH with Km values of 1.8 and 19.6 microM, respectively. Prolonged incubation of a hmp-lacZ fusion strain with the redox cycling agent paraquat resulted in a 28-fold induction of hmp gene expression, nearly 3-fold higher than after short periods of exposure. A strain overproducing Hmp was significantly more sensitive to paraquat than was the wild-type strain but, in vitro, purified Hmp was not an effective NADPH-paraquat diaphorase. Prolonged incubation of a wild-type strain with paraquat increased intracellular Hmp to spectrally detectable levels.
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PMID:Response of the NAD(P)H-oxidising flavohaemoglobin (Hmp) to prolonged oxidative stress and implications for its physiological role in Escherichia coli. 977 Feb 77

Topochemistry and activity of NADP-H diaphorase co-localized with NO synthase was examined in operative material of lungs from patients with bronchial asthma (BA), chronic nonobstructive bronchitis (CNO) and chronic obstructive bronchitis. The enzyme activity was found to be dependent upon the types of obstruction and inflammation. In CNO the state of NO synthase was not changed. In conditions of progressive irreversible airway obstruction the enzyme activity was augmented in small bronchi epithelium and alveolar macrophages (AM). In reversible obstruction the activity of NO synthase was not changed in the epithelium but appeared high in resident cells of inflammation--AM and mast cells.
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PMID:[The NADPH-diaphorase activity of the bronchial epithelium in chronic lung diseases]. 982 26

We present evidence about the possible use of histochemical NADP diaphorase reaction to visualize elements of the nervous system.
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PMID:[The NADP-diaphorase reaction as a neurohistologic method]. 988 2


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