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:1.6.99.3 (diaphorase)
5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochrome b5 was isolated from liver microsomes using a detergent-method. The hemoprotein was found to bind to liver plasma membranes in vitro and was accompanied by an increase in NADH-cytochrome c reductase activity, but not NADH-ferricyanide reductase activity. As in the case of microsomes, the binding to plasma membranes was temperature-dependent and was tight to the extent that the bound cytochrome b5 was little released under high ionic strength. The capacity of plasma membranes for the binding was less than that of microsomes. Administration of CCl4 did not significantly affect the binding of the hemoprotein in both fractions. These results add support to our previous proposal that the elevation of NADH-cytochrome c reductase activity of liver plasma membranes observed early after administration of CCl4 may be caused by the binding of cytochrome b5 which has probably migrated from the endoplasmic reticulum.
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PMID:Studies on the function of cell membrane. 11th Report: Binding of cytochrome b5 to liver microsomes and plasma membranes isolated from normal and CCl4-treated rats. 9 90

The involvement of cytochrome b5 in palmitoyl-CoA desaturation by yeast microsomes was studied by using yeast mutants requiring unsaturated fatty acids and an antibody to yeast cytochrome b5. The mutants used were an unsaturated fatty acid auxotroph (strain E5) and a pleiotropic mutant (strain Ole 3) which requires either Tween 80 and ergosterol or delta-aminolevulinic acid for growth. Microsomes from the wild-type strain possessed both the desaturase activity and cytochrome b5, whereas those from mutant E5 contained the cytochrome but lacked the desaturase activity. Microsomes from mutant Ole 3 grown with Tween 80 plus ergosterol were devoid of both the desaturase activity and cytochrome b5, but those from delta-aminolevulinic acid-grown mutant Ole 3 contained cytochrome b5 and catalyzed the desaturation. The cytochrome b5 content in microsomes from mutant Ole 3 could be varied by changing the delta-aminolevulinic acid concentration in the growth medium, and the desaturase activity of the microsomes increased as their cytochrome b5 content was increased. The antibody to yeast cytochrome b5, but not the control gamma-globulin fraction, inhibited the NADH-cytochrome c reductase and NADH-dependent desaturase activities of the wild-type microsomes. It is concluded that cytochrome b5 is actually involved in the desaturase system of yeast microsomes. The lack of desaturase activity in mutant Ole 3 grown with Tween 80 plus ergosterol seems to be due to the absence of cytochrome b5 in microsomes, whereas the genetic lesion in mutant E5 appears to be located at ther terminal desaturase.
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PMID:Mutant and immunochemical studies on the involvement of cytochrome b5 in fatty acid desaturation by yeast microsomes. 10 93

Measurement of the effect of drugs on the in vivo rates of synthesis of rabbit liver organelle bound proteins were measured following individual treatments with the inducers phenobarbital, 3-methylcholanthrene and PCB (a mixture of polychlorinated biphenyls) and the inhibitors, cycloheximide, aflatoxin B1, chloramphenicol and actinomycin D. Following their isolation from a homogenate containing the combined livers of 14C-leucine injected experimental animals and 3H-leucine injected control animals, purified fractions of the following proteins were prepared: microsomal cytochrome b5, cytochrome P-450, NADH-cytochrome b5 reductase, NADPH-cytochrome P-450 reductase and proteolipids, outer mitochondrial membrane cytochrome b5, NADH-cytochrome b5 reductase and proteolipids, inner mitochondrial membrane cytochrome c, NADH dehydrogenase and proteolipids, intermitochondrial membrane cytochrome b5 and circulating serum albumin. The effect of a drug was examined by measuring the 14C/3H ratio of leucine incorporation of each fraction; ratios which differed markedly from a control value of 1 represented actual changes in the relative rates of protein synthesis. Increased rates of synthesis of cytochrome P-450 and its reductase, intermitochondrial membrane cytochrome b5 and all three proteolipid fractions resulted from each inducer treatment. Treatments with 3-methylcholanthrene and PCB also increased the rate of synthesis of cytochrome b5 and its reductase in both the microsome and outer mitochondrial membrane. In addition, the PCB treatment increased the rates of synthesis of cytochrome c and NADH-dehydrogenase. The rates of synthesis of cytochromes, reductases and of circulating serum albumin were inhibited following treatments with cycloheximide, aflatoxin B1 and actinomycin D. Actinomycin D appeared to inhibit the release of newly synthesized albumin into the bloodstream while chloramphenicol treatment appeared to inhibit the incorporation of cytochrome c into the mitochondria. After 20 hours of treatment with inhibitors, the inhibitory effect of actinomycin D and cycloheximide were still apparent while the rates of protein synt;esis in chloramphenicol and aflatoxin B1 treated animals increased to levels above the controls. The incorporation of radioactively labeled leucine into the proteolipids of the microsomal, and the outer and inner mitochondrial membranes were inhibited following the treatment with actinomycin D and stimulated following the treatment with cycloheximide.
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PMID:Effect of a single dose of inducers and inhibitors on the rate of synthesis of cytochromes and reductases in liver organelles. 11 59

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.
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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 preparation of (R) and (S) [2(-3)H]lactate as well as (S) [2(-3)H] glutamate via the coupled exchange reaction catalyzed by NAD linked dehydrogenases and NADH: lipoamide oxidoreductase (diaphorase) is described. The specific radioactivity of the hydrogen ions of the 3HOH/H2O can be obtained in the substrates (100% exchange) if equilibrium isotope effects are disregarded. By the exchange procedure substrates with higher specific radioactivity are obtained from positionally [3H]labeled racemic mixtures prepared by chemical reductions with [3H]labeled hydrides. The tritium content of one of the enantiomeres is "washed out" into water. As examples are presented the preparation of (R) [2-3H] (S) [2-H]malate as well as the corresponding carnitine, glutamate and (R) and (S) lactate.
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PMID:Biochemical synthesis of stereospecifically hydrogen labeled compounds on a preparative scale, VI1-3 Synthesis of further substrates of NAD(P)-linked dehydrogenases of high specific tritium content. 12 62

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.
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PMID:Comparison of plasma membranes and endoplasmic reticulum fractions obtained from whole white adipose tissue and isolated adipocytes. 12 89

The properties of electron transport systems present in soluble and particulate fractions of spores of Bacillus megaterium KM?HAVE BEEN COMPARED WIth those of similar fractions prepared from exponential-phase vegetative cells of this organism. The timing and localization of modifications of the electron transport system occurring during sporulation have been investigated by using a system for separating forespores from mother cells at all stages during development [8]. Spore membranes contained cytochromes a + a3, and o at lower concentrations than in vegetative membranes, and in addition cytochrome c, which was not found in exponential-phase vegetative membranes. An NADH oxidase activity of similar specific activity was found in both spore and vegetative membranes but DL-glycerol 3-phosphate and L-malate oxidase activities were found only in vegetative membranes. A soluble NADH oxidase of low specific activity was found in spores and vegetative cells which probably involves a flavoprotein reaction with oxygen because the activity was stimulated by FAD or FMN and difference spectra of concentrated soluble fractions showed spectra typical of a flavoprotein. Particulate NADH oxidase was sensitive to all classical inhibitors of electron transport tested whereas soluble NADH oxidase was insensitive to many of these inhibitors. Cytochrome c was formed between stage I and II of sporulation and this coincided with a five-fold increase in NADH-cytochrome c reductase activity. Forespore membranes had lower contents of cytochromes than sporangial cell membranes but similar levels of NADH and L-malate oxidases; DL-glycerol 3-phosphate oxidase activity could not be detected in either membranes by stage III of sporulation. This characterization of spore electron transport systems provides a basis for suggestions concerning initial metabolic events during spore germination and the effect of a number of germination inhibitors.
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PMID:Morphogenesis of the membrane-bound electron-transport system in sporulating Bacillus megaterium KM. 12 54

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.
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PMID:Antigenic and enzymatic architecture of Micrococcus lysodeikticus membranes established by crossed immunoelectrophoresis. 12 77

Development of tumours of the urinarY bladder was studied in 59 Male and female Sprague-Dawley and Wistar rats with combined enzyme-histochemical and autoradiographic methods after oral application of n-butyl-n-(4-hydroxybutyl)-nitrosamine (BBN) and n-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT). as the first carcinogenic lesion detectable by light-microscopy a focal, sharply defined irreversible loss of alkaline phosphatase activity was consistently demonstrated in the urothelium, which appeared normal histologically and cytologically. In about 2/3 of the cases, NADH-diaphorase activity was markedly reduced in identical regions. The enzyme-deficient areas are to be considered as preneoplastic, because papillomas and carcinomas developed from them through different stages of hyperplasia. As a rule, these also were characterized by total loss of alkaline phosphatase activity and attenuation of the NADH-diaphorase in all parts or circumscribed areas. Autoradiographically 3H-thymidine-labelling index revealed a 43.2-fold (BBN) and 22.6-fold (FANFT) increase, respectively, in the enzyme-deficient areas, as compared with the surrounding emzyme-containing urothelium. After 54 hrs of continous labelling, there was a mean 3H-thymidine-labelling index of 54.9% in the enzyme-negative regions. The physiological mode of regeneration was no longer maintained in the areas of enzyme deficiency as there was an increased proliferation of suprabasal cells. Areas of papillomas that showed a marked attention of NADH-diaphorase had a 3H-thymidine-labelling index 4.5 (BBN) and 3.1 (FANFT) greater than the surrounding areas with preserved enzyme activity. Since loss of alkaline phosphatase activity occurs regulary and consistently after application of carcinogens with chemically different structures it appears to indicate the initial phase of tumor development in the urinary bladder of the rat.
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PMID:Focal loss of alkaline phosphatase and increase of proliferation in preneoplastic areas of the rat urothelium after administration of n-butyl-n-(4-hydroxybutyl)-nitrosamine and n-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide. 12 42

Measurement of certain membrane-bound enzymic activities was used to study the orientation of the outer membrane of the double-membraned forespore of Bacillus megaterium KM. 2. Adenosine triphosphatase, NADH dehydrogenase and L-malate intact protoplasts, but were readily detected in intact stage II or IV forespores, consistent with reversed polarity of the outer forespore membrane relative to the mother-cell plasma membrane. 3. Measurement of NADH oxidase activity revealed that intact stage III forespores had the same high affinity for NADH as protoplast membrane preparations and protoplast lystates, consistent with ready access of NADH to oxidation sites on the outer forespores membrane. 4. Forespores and protoplasts showed osmometric behaviour in solutions of non-permanent solutes consistent with the presence of an intact permeability barrier in these structures.
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PMID:Biochemical evidence for the reversed polarity of the outer membrane of the bacterial forespore. 13 69


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