NADH-ubiquinone oxidoreductase

Ragan, C I

doi:10.1016/0304-4173(76)90001-x

Cited by 121 publications

(32 citation statements)

References 82 publications

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“…This system, the first of several energy-conserving sites in mitochondrial electron transport, has been extensively studied and reviewed (18)(19)(20). We are not aware of a previous study of it in human fibroblasts.…”

Section: Resultsmentioning

confidence: 99%

“…The enzyme system has been studied thoroughly in preparations from beef heart mitochondria and, to a lesser extent, in yeast (19). Despite the considerable literature on this system, the mechanism of NADH oxidation, the functional organization of complex I in the inner mitochondrial membrane, and its molecular structure remain obscure (20). Ubiquinone is the natural acceptor for electrons released in the oxidation of NADH, and ferricyanide is the most efficient artificial electron acceptor.…”

Section: Resultsmentioning

confidence: 99%

“…Despite the complexity and controversy that exist there are several important points of agreement concerning mitochondrial NADH dehydrogenase: (i) it is the site of entry of NADH into the respiratory chain; (ii) it catalyzes the dehydrogenation of NADH generated through oxidation of numerous NAD+-linked dehydrogenase reactions; (iii) it is the first of three en--ergy-conserving sites where ATP is formed; (iv) it is one of three sites of uphill Ca2+ influx into mitochondria; and (v) it is specifically inhibited by several agents including rotenone (18)(19)(20)(21).…”

Section: Resultsmentioning

confidence: 99%

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Mitrochondrial NADH dehydrogenase in cystic fibrosis.

Shapiro¹,

Feigal²,

Lam³

1979

Proc. Natl. Acad. Sci. U.S.A.

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We have shown that skin fibroblasts from patients with cystic fibrosis (CF) and from carriers for CF [heterozygotes (HZ)] consume more 02 than do their controls. When the mitochondrial electron transport inhibitor rotenone was added to the cells, the relative inhibition of 02 consumption was CF > HZ > controls (P < 0.005 in both comparisons). Because rotenone specifically inhibits NADH dehydrogenase, [NADH:(acceptor) oxidoreductase, EC 1.6.99.31, which is the enzyme of energy-conserving site 1 of the mitochondrial electron transport system, activity and kinetics of this enzyme system were studied in fibroblast homogenates. NADH dehydrogenase activity was equal in cells from the three genotypes. At pH 8.0, affinity of the enzyme for its substrate was CF < HZ = controls; at pH 8.6, affinity was CF> HZ = controls (P < 0.005 for the differences). pH optima for the genotypes were without exception 8.6 (CF), 8.3 (HZ), and 8.0 (control). HZ and control lines were distinguished unequivocally in a blind test on the basis of differences in pH optima. Purified mitochondrial preparations revealed pH optima identical to those found in whole cell homogenates. These data suggest that the mutant gene responsible for CF is expressed in the complex mitochondrial NADH dehydrogenase system.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Mitrochondrial NADH dehydrogenase in cystic fibrosis.

Shapiro¹,

Feigal²,

Lam³

1979

Proc. Natl. Acad. Sci. U.S.A.

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“…This is illustrated in Fig. 10(a) (Rieske, 1976) and 850000 for Complex I (Ragan, 1976b)], although the molecular dimensions of Complex I are unknown. The ubiquinone-containing interface need not contain phospholipid if the approach of the two Complexes is close.…”

Section: Discussionmentioning

confidence: 99%

The effects of lipid phase transitions on the interaction of mitochondrial NADH–ubiquinone oxidoreductase with ubiquinol–cytochrome c oxidoreductase

Heron¹,

Gore²,

Ragan³

1979

Biochemical Journal

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1. The endogenous phosphatidylcholine and phosphatidylethanolamine of Complexes I and III from bovine heart mitochondria may be completely replaced with 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine with at least partial retention of activity. 2. The lipid-replaced enzymes associate in 1:1 molar ratio to give a Complex I–III unit catalysing NADH-cytochrome c oxidoreductase activity. 3. On increasing the concentration of ubiquinone-10 and the synthetic phospholipid, the lipid-replaced Complexes appear to operate independently of each other as in the natural membrane. Thus the lipid-replaced enzymes associate in exactly the same ways as the enzymes containing natural phospholipids. 4. Arrhenius plots of NADH–cytochrome c oxidoreductase activity reconstituted from lipid-replaced Complexes I and III exhibit changes in slope at 24 degrees C. When the concentrations of phospholipid and ubiquinone-10 are increased, the Arrhenius plots show discontinuities at 24 degrees C as well as changes in slope. 5. The kinetics of cytochrome b reduction by NADH were measured in mixtures containing 2 mol of Complex III/mol of Complex I. When the enzymes contained natural phospholipids. the reduction kinetics were biphasic. When the enzymes had been supplemented with further phospholipid and ubiquinone-10 the kinetics were monophasic. When lipid-replaced enzymes were supplemented with 1,2-ditetradecanoyl-sn-glycero-3-phosphocholine and ubiquinone-10, reduction of cytochrome b was monophasic above the phase-transition temperature of the lipid but biphasic below it. 6. These findings are interpreted in terms of the model for the interaction of Complexes in the natural membrane proposed by Heron, Ragan & Trum-power [(1978) Biochem. J. 174, 791–800].

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“…There are numerous procedures to isolate NADH dehydrogenases from animal mitochondria (7)(8)(9)23) and bacteria (2,16,25). In contrast, procedures to isolate plant mitochondrial NADH dehydrogenases are limited (5).…”

mentioning

confidence: 99%

Separation Procedure and Partial Characterization of Two NAD(P)H Dehydrogenases from Cauliflower Mitochondria

Klein¹,

Burke²

1984

Plant Physiol.

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A procedure was developed to separate ad partially purify two NAD(P)H dehydrogenases from the inner membrane of cauliflower (Brsica okrcca L.) mitochondria. The procedure used Triton X-100 extraction followed by (NH4)2SO4 precipitation and gel filtration (Sepharose G-200 column) chromatography. The first dehydrogenase fraction (which elated in the column void volume) was specific for NADH, was stimulated by KO addition, and MATERIALS AND METHODS Mitochondrial Isolation. Mitochondria were isolated from cauliflower essentially as described by Ikuma and Bonner (10). Both the grinding and wash media, however, were supplemented with 20 mm Hepes buffer (pH 7. 1).Preparation of Mitoplasts. Methods used to subfractionate mitochondria were similar to those of Watrud et al. (26). However, modification of this subfractionation procedure was necessary to obtain mitoplasts (inner membrane plus matrix) free of outer membrane fragments. The modified procedure is given below.Percoll gradient-purified mitochondria (10-14 mg of mitochondrial protein) were collected and concentrated by centrifugation (12,000g for 5 min) according to standard procedures (12). The 12,000g supernatant fraction was discarded, and the pellet was resuspended in a minimal amount (<1.0 ml) of cold 10 mm phosphate buffer (pH 7.2) containing 1 mg/ml BSA. The mitochondrial suspension was slowly diluted with enough 10 mM phosphate buffer to reach a final volume ranging from 6 to 10 ml (approximately 1.5 mg/ml mitochondrial protein) and homogenized for 10 min in a Brinkman polytron2 (300 rotating strokes/min). The sucrose concentration was adjusted to 0.3 M by the addition of 1.8 M sucrose containing 2 mm MgSO. and 4 mM ATP. The suspension was homogenized for 5 min and then layered on discontinuous sucrose gradients (0.74, 1.10, and 1.25 M) that contained 10 mm phosphate buffer (pH 7.2) and I mg/ ml BSA. Gradients were centrifuged at 27,600g for 4 h in a Sorvall model HB-4 swinging bucket rotor at 4°C. The mitoplast ' Abbreviations: EPR, electron paramaetic resonance; N-decyl ubiquinone, 6-decyl-2,3-dimethoxy-5-methyl-1,4benzoquinone; CMS, pchloromercuriphenylsulfonic acid; CMB, p-chloromercuribenzoate.

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NADH-ubiquinone oxidoreductase

Cited by 121 publications

References 82 publications

Mitrochondrial NADH dehydrogenase in cystic fibrosis.

Mitrochondrial NADH dehydrogenase in cystic fibrosis.

The effects of lipid phase transitions on the interaction of mitochondrial NADH–ubiquinone oxidoreductase with ubiquinol–cytochrome c oxidoreductase

Separation Procedure and Partial Characterization of Two NAD(P)H Dehydrogenases from Cauliflower Mitochondria

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