Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Differential centrifugation was applied to adult and foetal liver of monkey. Obtained fractions were: F1 (800 X g); F2 (12 500 X g); F3 (200 000 X g); and cell sap. Analysis of chemical compounds of these fractions shows that: (1) adult and foetal nucleic acids levels are similar; (2) there are more proteins in adult than in foetal hepatocytes; (3) most of the glycogen is located in F3; the foetal level is twenty times higher than the adult level. Plasma membrane enzymes (5'-nucleotidase, adenylate cyclase) show a nucleomicrosomic distribution. The distribution of alkaline phosphatase is not significant. Mitochondrial enzymes (monoamine oxydase, succinate cytochrome c reductase, cytochrome oxydase) are enriched in F2 without any sedimentation in F3. There is more malate dehydrogenase liberated in cell sap during foetal liver fractionation. This indicates the foetal mitochondria are more sensitive to the homogenisation method. Lysosomal enzymes (acid phosphatase, N-acetylglucosaminidase) are enriched in F2. The same observation for N-acetylglucosaminidase as for malate dehydrogenase leads to the same conclusion for foetal lysosomes. Endoplasmic reticulum and Golgi enzymes (glucose-6-phosphatase and related phosphotransferase activity, NADPH-cytochrome c reductase and sialytransferase) are much enriched in F3. Thus this fraction F3 is pure enough to allow the observation of the modification produced on endoplasmic reticulum and Golgi apparatus during foetal and neonatal development.
Biochim Biophys Acta 1979 Sep 20
PMID:[Comparative study of microsomal enzymic activities in adult and foetal monkey hepatocytes (author's transl)]. 11 30

In our previous papers, tiopronin (2-mercaptopropionylglycine) and glutathione were reported to suppress the liver damage induced by ethionine. In the damage induced by ethionine. In the present study, we evaluated such suppressive effect from the aspect of drug metabolizing activity. Aniline hydroxylating enzyme activity and aminopyrine N-demethylating enzyme activity of the liver microsome of rats 24 hr after administration of 1 g/kg ethionine were decreased to 53.2% and 61.7% respectively as compared with those of the normal rats. Administration of tiopronin or glutathione to the ethionine treated rats suppressed the decrease of both enzyme activities induced by ethionine. Ethionine did not influence NADH-cytochrome c reductase (fp1) but brought about increase of the activity of NADPH-cytochrome c reductase (fp2) and decrease of the cytochrome P-450 content. These thiol compounds did not influence fp1 and fp2 but tended to suppress the cytochrome P-450 content decreased by administration of ethionine. In particular, tiopronin suppressed the content significantly. Disappearance of aminopyrine, hexobarbital and pentobarbital from the blood was markedly delayed by ethionine administration. It was revealed, however, that such delay was recovered by tiopronin or glutathione. The sleeping time induced by hexobarbital and pentobarbital was also prolonged by ethionine, but this tended to be shortened by tiopronin or glutathione.
Nihon Yakurigaku Zasshi 1979 Sep
PMID:[Effect of thiol compounds on experimental liver damage (III). Effect of tiopronin (2-mercaptopropionylglycine) and glutathione on drug metabolizing activity (author's transl)]. 12 Feb 98

The influence of the mode of preparation upon some of the characteristics of white adipose tissue plasma membranes and microsomes has been reported. Plasma membrane fractions prepared from mitochondrial pellet were shown to have higher specific activities of (Mg2+ + Na+ + K+)-ATPase than plasma membranes originating in crude microsomes. Isolation of fat cells by collagenase treatment was found to result in a decrease in specific activity of the plasma membrane enzymes; in plasma membranes prepared from isolated fat cells, the specific activity values obtained for (Mg2+ + Na+ +k+)-ATPase and 5'-nucleotidase were only 42% and 6.3% respectively of those obtained in plasma membranes prepared from whole adipose tissue. Purification of whole adipose tissue crude microsomes by hypotonic treatment caused extensive solubilization of the endoplasmic reticulum marker enzymes, NADH oxidase and NADPH cytochrome c reductase. The lability of endoplasmic reticulum marker enzymes, however, was found to be greatly diminished in the preparations from isolated fat cells. The possibility that NADH oxidase and NADPH cytochrome c reductase activities found in the plasma membranes are microsomal enzymes adsorbed by the plasma membranes is discussed. The peptide patterns as well as the NADH oxidase and NADPH cytochrome c reductase activity patterns of plasma membranes and purified microsomes were compared by means of sodium dodecyl sulfate or Triton X-100 polyacrylamide gel electrophoresis.
Biochim Biophys Acta 1975 Sep 16
PMID:Comparison of plasma membranes and endoplasmic reticulum fractions obtained from whole white adipose tissue and isolated adipocytes. 12 89

By crossed immunoelectrophoresis with membrane antiserum, 17 antigens have been detected in fractions from plasma membranes of M. lysodeikticus solubilized with Triton X-100. Absorption tests with protoplasts have demonstrated that eight of the antigens are expressed on the surface. Of these antigens the major one has been identified as a succinylated mannan. Five of the principal immunoprecipitates unaffected by absorption with protoplasts were shown by zymograms to possess the following enzymic activites: succinate dehydrogenase (EC 1.3.99.1), ATPase (EC 3.6.1.3), NADH dehyrogenase (EC 1.6.99.3)(two separate components), and malate dehydrogenase (EC 1.1.1.37). These enzymes or enzyme-complexes are, therefore, not expressed on the outer surface of the protoplast membrane.
Proc Natl Acad Sci U S A 1975 Sep
PMID:Antigenic and enzymatic architecture of Micrococcus lysodeikticus membranes established by crossed immunoelectrophoresis. 12 77

Four cytoplasmic mutants of Saccharomyces cerevisiae showing loss of mitochondrial rutamycin-sensitive ATPase activity but having significant cytochrome oxidase and NADH-cytochrome c reductase have been isolated. Genetic studies indicate the mutations to be closely linked to each other and have been assigned to a new locus, PHO1. The mutations show a low frequency of recombination with the OL12 locus, suggesting a linkage to this marker. They are not, however, linked to the OLI1 locus. Linkage of the ATPase mutations to the OLI2 locus is also indicated by restoration of wild-type diploids by sigma- clones that retain the segment of mitochondrial DNA carrying OLI2. Based on the recombinants issued from crosses of the mutants with a triple drug-resistant strain and an analysis of the resistance markers present in sigma- clones that are effective in restoring a wild-type phenotype, the PHO1 locus has been placed in the segment of DNA located between PAR1 and OLI2.
Eur J Biochem 1976 Sep
PMID:Localization on mitochondrial DNA of mutations leading to a loss of rutamycin-sensitive adenosine triphosphatase. 13 92

The Neurospora crassa assimilatory NAD(P)H-nitrite reductase complex has associated a NAD(P)H-diaphorase activity. 1. This NAD(P)H-diaphorase activity can use either mammalian cytochrome c, 2,6--dichlorophenol-indophenol, ferricyanide, or menadione as electron acceptor from the reduced pyridine nucleotides, and requires flavin adenine dinucleotide for maximal activity. 2. It is inhibited by p-hydroxymercuribenzoate, 1 muM, and it is unaffected by cyanide, sulfite, or arsenite at concentrations which completely inhibit the NAD(P)H-nitrite reductase activity. 3. Flavin adenine dinucleotide specifically protects the NAD(P)H-diaphorase activities, but not the NAD(P)H-nitrite reductase activities, against thermal inactivation. 4. In vitro preincubation of the Neurospora crassa nitrite reductase complex with reduced pyridine nucleotides plus flavin adenine dinucleotide inactivates the NAD(P)H-nitrite reductase activities, but does not affect the NAD(P)H-diaphorase activities, indicating that this nitrite reductase inactivation occurs in the part of the enzyme that contain the nitrite reducing center.
Arch Microbiol 1976 Sep 01
PMID:A reduced pyridine nucleotides-diaphorase activity associated to the assimilatory nitrite reductase complex from Neurospora crassa. 13 35

The primary catabolic pathways in the fungi Penicillium notatum and P. duponti, and Mucor rouxii and M. miehei were examined by measuring the relative rate of 14CO2 production from different carbon atoms of specifically labelled glucose. It was found that these organisms dissimilate glucose predominantly via the Embden--Meyerhof pathway in conjunction with the tricarboxylic acid cycle and to a lesser extent by the pentose phosphate pathway. Phosphofructokinase (EC 2.7.1.11) activity could not be detected initially in Penicillium species because of the interference from mannitol-1-phosphate dehydrogenase (EC 1.1.1.17) and NADH oxidase (EC 1.6.99.3). A combination of differential centrifuging and a heat treatment of Penicillium cell-free extracts in the presence of fructose-6-phosphate removed the interfering enzymes. The kinetic characteristics of phosphofructokinase from P. notatum and M. rouxii are described. The enzyme presents highly cooperative kinetics for fructose-6-phosphate. The kinetics for ATP show no cooperativity and inhibition by excess ATP is observed. The addition of AMP activated the P. notatum enzyme, relieving ATP inhibition; slight inhibition by AMP was observed with the M. rouxii enzyme. In contrast M. rouxii pyruvate kinase (EC 2.7.1.40) is activated 50-fold by fructose-1,6-diphosphate whereas pyruvate kinase from P. notatum and P. duponti were unaffected by fructose-1,6-diphosphate.
Can J Microbiol 1977 Sep
PMID:Phosphofrucktokinase and glucose catabolism of Mucor and Penicillium species. 14 38

(1) Aerobic incubation of heart muscle submitochondrial particles in phosphate buffer after treatment with NADH causes a progressive and substantial inhibition of the NADH oxidation system. Succinate oxidation remains almost unaffected by NADH treatment. (2) The loss of NADH oxidase activity is due to an inhibition of the respiratory chain-linked NADH dehydrogenase. This inhibition of the enzyme is very similar to that caused by combination of the organic mercurial mersalyl with NADH dehydrogenase. (3) The inhibition of NADH oxidation is largely prevented by compounds that are known to react with superoxide ions (02-.), including superoxide dismutase, cytochrome c, tiron and Mn2+. EDTA also has a protective effect, but a number of other metal chelating agents, and several proteins, including catalase, are without effect. (4) It is concluded that the inhibition of NADH oxidation of NADH oxidation by superoxide ions or by mersalyl is reversible and is therefore not due to the loss of oxidoreduction components from the respiratory chain or to an irreversible change in protein conformation. (6) The function of mitochondrial superxide dismutase is discussed in relation to the key role of NADH dehydrogenase in energy-conserving reactions and the formation of hydrogen peroxide during mitochondrial oxidations.
Biochim Biophys Acta 1975 Sep 08
PMID:A protective function of superoxide dismutase during respiratory chain activity. 16 98

1. An NADH dehydrogenase, obtained from an extremely halophilic bacterium, was activated by various salts when enzyme activity was measured as the observed velocity, whereas the maximum velocity was unaffected by either the salt concentration or the nature of the salt. 2. Two ion effects were observed; a quantitative cation effect, reflected in changes in the apparent Michaelis constant for 2,6-dichlorophenolindophenol, and a qualitative anion effect, reflected in the apparent Michaelis and dissociation constants for NADH. 3. The data suggest that cations act by neutralizing electrostatic charges surrounding the 2,6-dichlorophenolindophenol-binding site, whereas the anions affect the conformation of the enzyme by altering the accessibility of the NADH-binding site to the bulk solvent. 4. Thus, the apparent activation of this enzyme, obtained from an extremely halophilic bacterium, is a reflection of measuring enzyme activity at non-saturating substrate concentrations.
Biochim Biophys Acta 1975 Sep 22
PMID:Studies of a halophilic NADH dehydrogenase. II. Kinetic properties of the enzyme in relation to salt activation. 16 11

The purification of iodinated (E. B. McGowan and E. Stellwagen (1970), Biochemistry 9, 3074) and of nitrated (M. Sokolovsky et al. (1970), Biochemistry 9, 5113) cytochromes c resulted in the recovery from the former preparation of diiododityrosyl-cytochrome c (DIDT-) with modification of Tyr-67 and Tyr-74, and, from the latter, a mononitromonotyrosyl-cytochrome c (MNMT-), with modification of Tyr-67, and mononitrodityrosyl-cytochrome c (MNDT-), with the added modification of Tyr-48. The three purified preparations were conformationally characterized using pH-spectroscopy, circular dichroism, thermal denaturation, reducibility with ascorbate, autoxidation with molecular oxygen, and binding with CO. These results are related to the two aspects of biological function, reducibility, measured by NADH-cytochrome c reductase, and oxidizability, with cytochrome c oxidase, as well as to structure-function relationships in the protein. MNMT-cytochrome c was found to be, structurally and conformationally, a single isomer, reducible with ascorbate, with a small, but definite affinity for both oxidation with molecular oxygen and binding of CO. Conformationally, in both valence states of the metal atom, it represents a molecular form with native-like conformation with small but definite perturbations in the immediate vicinity of the heme group, reflected by the destabilization of the Met-80-S-Fe linkage. MNMT-ferricytochrome c exhibits a pK of 6.2 for the transformation of the low-spin, native-like spectral form II containing the 695-nm band to form lacking lacking the 695-nm band. The isomerization at pK = 6.2, when analyzed in terms of the isomerization of the native protein with a pK of 9.2 and the nature of the group involved, indicates that Tyr-67 is not involved in the isomerization of the modified preparation, and possibly not in the native protein as well. In terms of biological function, the partial derangement of redecibility (24%) and the unaltered oxidizability point to the functional significance of Tyr-67, and provide another example of selectivity between the two aspects of physiological functional function, in agreement with the two-function, two-path operational model of the protein. The MNDT- and DIDT-ferricytochromes c exhibited physicochemical properties indicative of gross derangement of both the conformation of the protein as well as of the coordination configuration of the metal atom. The complete inability to accept an electron from NADH-cytochrome c reductase in both cases, and the retention of 50% of the oxidizability property of DIDT-cytochrome c, were interpreted to be the result of conformational derangement, rather than the added modification of Tyr-48 or of Tyr-74.
Biochemistry 1975 Sep 23
PMID:Conformational and functional studies of chemically modified cytochrome c: nitrated and iodinated cytochromes c. 17 Sep 59


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