Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of M7310U, a new non-steroidal analgesic anti-inflammatory agent, on liver microsomal drug-metabolizing enzymes was investigated. Rats were treated orally with M73101 (100, 200, 500 mg/kg), henylbutazone (PZ, 200 mg/kg), aminopyrine (AM, 100 mg/kg) or phenobarbital sodium (PB, 100 mg/kg) once daily for 2 weeks and then were observed for 2 weeks during which treatment was not given. On treatment with M73101, PZ, AM and PB, the liver enlarged but was restored to normal 1 week after the last administration. The rate of increase in the case of M73101 was lower than that seen with the reference compounds. M73101 markedly increased the content of microsomal protein, cytochrome P-450 or b5 and NADPH cytochrome C reductase, aniline hydroxylase and AM demethylase activity, but these increments returned to the normal level 1 week after the last administration. The serum concentration of M73101 after repeated administration (200 mg/kg, p.o.) for 1 week was lower than that after a single administration. Furthermore, M73101 increased Vmax for both aniline hydroxylase and AM demethylase, whereas it increased Km only for aniline hydroxylase. M73101 did not enhance the lipid peroxidation. Our observations suggest that the enlargement of rat liver seen with M73101 was due to the induction of drug-metabolizing enzymes and that this agent can probably be classified as a phenobarbital-type inducer.
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PMID:[Pharmacological studies of 4-ethoxy-2-methyl-5-morpholino-3(2H)-pyridazinone (M73101). (4). Enzyme induction (author's transl)]. 12 Mar

The effects of addition of purified NADPH-cytochrome c (P-450) reductase on microsomal activities of aniline hydroxylation, p-phenetidine O-deethylation and ethylmorphine and aminopyrine N-demethylations were investigated utilizing microsomes from untreated, phenobarbital-treated and 3-methylcholanthrene-treated rats. The purified reductase was incorporated into microsomes. The drug oxidation activities were increased by the fortification of microsomes with the reductase while the extent of increase in the activities varied with the substrate and microsomes employed. The most pronounced enhancement was seen in p-phenetidine O-deethylation, followed by aniline hydroxylation and aminopyrine and ethylmorphine N-demethylations. The enhancement was more remarkable in microsomes from rats treated with 3-methylcholanthrene or phenobarbital. alpha-Naphthoflavone inhibited p-phenetidine O-deethylation activity markedly when the reductase was incorporated into microsomes, indicating that a larger amount of a species of cytochrome P-450 sensitive to the inhibitor was capable of participating in the oxidation of this substrate in the presence of the added reductase. One of the two Km values seen with higher concentrations of aniline or aminopyrine was altered by the fortification of microsomes with the purified NADPH cytochrome c (P-450) reductase. From these results, we propose that NADPH-cytochrome c (P-450) reductase transfers electrons to the selected one or two of multiple species of cytochrome P-450 more preferentially depending upon the substrate and the concentration of the substrate in microsomal membranes.
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PMID:Stimulation of microsomal drug oxidation activities by incorporation into microsomes of purified NADPH-cytochrome c (P-450) reductase. 12 Apr 63

M. phlei, grown on synthetic Sauton medium (with 6% glycerol as carbon source), had NADPH- and NADH-aldopentose reductase, as well as NAD-pentitol dehydrogenase activities; some of their properties are studied. These activities are not present in BCG grown on the same medium. All experiments of aldopentose-reductase induction in BCG on a D(+)xylose medium were negative.
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PMID:[Enzymes catalyzing the reduction of aldopentoses and the oxidation of pentitols in Mycobacteria]. 12 Jul 78

In order to document testicular 17beta-reduction deficiency (17RD) and to search for additional metabolic aberrations possibly associated with this disorder, the metabolism of 14C-labeled pregnenolone (delta5P), 17-HYDROXYPROGESTERONE (17OHP), dehydroepiandrosterone (DHEA), androstenedione (A), testosterone (T) and estrone (E1) was studied in testicular minces from a 46-year-old male pseudohermaphrodite (MPH) with highly elevated testicular A and minimal T secretion but normal extragonadal conversion of A to T. Testicular minces from a 20-year-old MPH with apparently normal testicular T biosynthesis served as a control. The results of this investigation show that the 17RD testes metabolized delta5P along delta5- and delta4- pathways but, in contrast to the control, converted more 17OHP, metabolizing it predominantly to A rather than T, failed to reduce DHEA to androst-5-ene-3beta,17beta-diol, metabolized DHEA very efficiently to A and produced little T, and converted only minimal quantities of A and E1 to their 17beta-reduced counterparts. 17beta-Reduction increased slightly but was far from being restored to control levels upon addition of NADH plus NADPH. However, oxidation of T to A by 17RD testicular minces, with and without additional NAD plus NADP, was comparable to that by the control. These results document 17RD for A, DHEA and E1 and suggest that the lack of elevated 17OHP and DHEA secretion by the 17RD testes was due to increased 17, 20-lyase and perhaps elevated 3beta-hydroxysteroid dehydrogenase and/or isomerase activity. The observation that 17beta-reduction was only slightly increased upon addition of NADH plus NADPH, but that oxidation of T to A was normal, is consistent with the assumption that more than one 17beta-hydroxysteroid dehydrogenase may be involved in testicular 17beta-reduction and/or 17-oxidation, and that the 17RD testes studied either lacked the enzyme which acts predominantly as 17beta-reductase or that the affinity of this 17beta-reductase for reduced cofactor(s) and/or substrates was abnormal.
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PMID:In vitro steroid metabolic studies in testicular 17 beta-reduction deficiency. 12 61

Scolices and brood capsules of healthy hydatid cysts from lungs of human patients were studied with histochemical and histoenzymatic methods. The subtegumental and flame cells were sepcially rich in glycogen, RNA and some dehydrogenases such as SDH, MDH, NADH-reductase and G-6-PDH. The rostellar zone or invaginated pole, an area of marked contractile movements, showed intense activity in ATP'ase and simple esterase. The so-called excretory pole shows strong activity in simple esterases, lipase, beta-HBH, alpha-GDH and NADPH-reductase. Lipids are also abundant in this zone implying the important role of this metabolic path in the development of the parasite. Intense activity in alkaline phosphatase was observed in cells associated to the calcereous corpuscles. The largest corpuscles were devoid of enzymatic activity. The enzyme could play some role in the calcification of the corpuscles. Wide enzymatic variations are described according to morphology being orthoscolices the most rich in enzyme activity. Accumulations of small cells surrounded by specialized cells on the germinal membrane are interpreted as the origin or "embryo" of brood capsules. Some enzymes detected in the wall of mature brood capsules depicted alternating types of cells. Some of them are positive for ATP'ase that may be related to active transport of substances across the brood capsule wall. The intenst ATP'ase activity at the stalks of scolices may be similarly interpreted. However, a miosine-like activity is a more feasible explanation since this area showed striking contractile movements in vivo.
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PMID:Histochemistry and histoenzymology of the hydatid cyst (Echinococcus granulosus Batsch, 1786). II. Scolices and brood capsules. 13 Jul 50

Data regarding the role of oxygen in nitrite reduction are presented. In an NADPH-generating system including homogeneously purified ferredoxin-NADP reductase, ferredoxin (or flavodoxin) and nitrite reductase from the alga Bumilleriopsis filiformis, oxygen and nitrite can be reduced simultaneously. In air, rates of 1.2 mumol nitrite reduced-min-1-mg-1 nitrite reductase are obtained, which are physiologically feasible. Ferredoxin is inhibited non-competitively by oxygen during nitrite reduction. Oxygen uptake due to the oxidase reaction of ferredoxin-NADP reductase mediated by flavodoxin from Chlorella fusca and ferredoxin from Bumilleriopsis involves superoxide and is inhibited by the nitrite reducing system.
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PMID:The influence of oxygen on nitrite reduction in a reconstituted system. 13 27

It has been found that metyrapone can inhibit both type I and type II mixed-function oxygenase reactions, while cysteamine inhibits only type I activity in this mammalian system. Following pretreatment with phenobarbital and 3-methylcholanthrene the half-maximal inhibiting concentrations for the O-demethylation of paranitranisol are increased for cysteamine and decreased for metyrapone. Both cysteamine and metyrapone give type II binding spectra with oxidized cytochrome P-450. The negative and positive peaks are at 393 and 426 nm respectively for metyrapone, and 410 and 434 nm for cysteamine. Cysteamine showed no binding comparable to that of metyrapone for reduced cytochrome P-450. Metyrapone showed little or no inhibition of the NADH cytochrome-c reductase (EC 1.6.1.1) or NADPH (EC 1.6.2.3) cytochrome-c reductase while cysteamine had a more or less strong inhibiting effect depending on the pretreatment of animals. Neither the binding to P-450 heme nor the inhibition of NADH and NADPH cytochrome-c reductase correlates well with cysteamine inhibition of total activity. It is therefore suggested that cysteamine reacts with an intermediate electron carrier of non-heme iron or glycoprotein character thus inhibiting mixed-function oxygenase activity.
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PMID:A comparative study on the influence of cysteamine and metyrapone on mixed-function oxygenase activities in variously pretreated liver microsomes from rats and mice. 13 29

Cytochrome P-450 has been purified from liver microsomes of phenobarbital-induced rabbits in the presence of ionic and nonionic detergents to concentrations over 17 nmoles per mg of protein. The purified cytochrome P-450 LM gives a single major band on SDS-polyacrylamide gel electrophoresis representing about 90 per cent of the total protein. The polypeptide chain has a molecular weight of about 49,000 daltons. NADPH-cytochrome P-450 reductase has been purified from liver microsomes of phenobarbital-induced rats in the presence of ionic and nonionic detergents to a stage where it catalyzes the reduction of 33,000 nmoles of cytochrome c per min per mg of protein. The ratio of activities toward cytochrome P-450 and cytochrome c is constant throughout purification. The purified reductase contains equimolar amounts of FMN and FAD and gives a single major band on SDA-polyacrylamide gel electrophoresis accounting for about 70 per cent of the total protein; the molecular weight is about 80,000 daltons. The purified cytochrome P-450 is free of cytochrome b5 but contains another electron acceptor, provisionally called Factor C, which is equivalent in amount to the heme present. Two electrons are taken up per molecule of cytochrome P-450 from dithionite or from NADPH in the presence of catalytic amounts of the reductase, and both electrons are readily transferred from the reduced cytochrome P-450 to molecular oxygen or artificial electron acceptors. The reconstituted enzyme system containing purified cytochrome P-450, purified NADPH-cytochrome P-450 reductase, and phosphatidylcholine retains the ability to catalyze the hydroxylation of drugs, fatty acids, hydrocarbons, and aniline in the presence of NADPH and molecular oxygen.
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PMID:Biochemical characterization of highly purified cytochrome P-450 and other components of the mixed function oxidase system of liver microsomal membranes. 16 50

The objective of this investigation was to find out whether vitamin E deficiency, apart from influencing the lipid component of cellular membranes, also influences the protein component. For that purpose a number of membrane-bound enzymes in the liver of the Pekin duckling were histochemically, cytochemically, and biochemically examined. Furthermore, cells, cellular membranes, and protein particles in membranes were morphometrically investigated. Histochemically five membrane-bound enzymes appeared to be stimulated in vitamin E deficiency: 5'-nucleotidase, glucose-6-phosphatase, isocitrate dehydrogenase (NADP), tetrazolium reductase (NADH), and tetrazolium reductase (NADPH). 5'-Nucleotidase and glucose-6-phosphatase were also investigated cytochemically and biochemically. The cytochemical localization of these enzymes was identical in control and vitamin E-deficient ducklings. Biochemically, a stimulation of these two enzymes also could be demonstrated. The increase per milligram of DNA appeared to be largest whereas the increase per milligram of protein, per milligram of phospholipid, and per milligram of RNA was only half of the increase per milligram of DNA. This can be explained by the 30 per cent increase of the cell volume in vitamin E deficiency leading to an increase of protein, phospholipid, and RNA per cell. The thickness of membranes and the diameter of protein particles in membranes were measured in liver parenchymal cells. In vitamin E deficiency the thickness of the outer mitochondrial membrane and the diameter of protein particles in this membrane were smaller whereas the thickness of the endoplasmic reticular membrane was larger. The increase of the activities of mitochondrial and microsomal enzymes and the decrease of the thickness of the outer mitochondrial membrane and of its protein particles are interpreted to be the result of the influence of free radicals on membranes with electron transport functions. The increase of 5'-nucleotidase activity in the plasma membrane is likely to have a different cause; it may be related to the transport of nucleotides across this membrane.
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PMID:Cellular membranes and membrane-bound enzymes in vitamin E deficiency. A histochemical, cytochemical, biochemical, and morphologic study of the liver of the Pekin duckling. 16 37

An improved procedure for the preparation of cobalt-cytochrome c has been developed. Various factors influencing the cobalt insertion process are discussed. The optical spectra of cobalt-cytochrome c suggest a six-coordinated species. The spectral shifts occurring with oxidation-reduction are compared with those observed for deoxy-cobaltohemoglobin and ferrocytochrome c and attributed to the effect of d(z2) electron on stereoelectronic interactions between the axial ligands and the porphyrin pi systems. Cobalt-cytochrome c has Em,7 = -140 +/- 20 mV as compared to an Em,7 of +250mV for ferrocytochrome c. An explanation for this negative Em,7 is offered. Cobaltocytochrome c is oxidized by cytochrome oxidase at about 45% of the rate for native cytochrome c. On the other hand cobalticytochrome c was not reduced by microsomal NADH or NADPH cytochrome c reductase nor by mitochondrial NADH or succinate cytochrome c reductase. It appears that the integrity of the reductase binding site is destroyed and the oxidase binding site has been modified by cobalt substitution.
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PMID:Cobalt-cytochrome c. I. Preparation, properties, and enzymic activity. 16 80


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