1
|
Selak MA, Lyver E, Micklow E, Deutsch EC, Önder Ö, Selamoglu N, Yager C, Knight S, Carroll M, Daldal F, Dancis A, Lynch DR, Sarry JE. Blood cells from Friedreich ataxia patients harbor frataxin deficiency without a loss of mitochondrial function. Mitochondrion 2011; 11:342-50. [PMID: 21147271 PMCID: PMC4419809 DOI: 10.1016/j.mito.2010.12.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 11/15/2010] [Accepted: 12/03/2010] [Indexed: 12/18/2022]
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by GAA triplet expansions or point mutations in the FXN gene on chromosome 9q13. The gene product called frataxin, a mitochondrial protein that is severely reduced in FRDA patients, leads to mitochondrial iron accumulation, Fe-S cluster deficiency and oxidative damage. The tissue specificity of this mitochondrial disease is complex and poorly understood. While frataxin is ubiquitously expressed, the cellular phenotype is most severe in neurons and cardiomyocytes. Here, we conducted comprehensive proteomic, metabolic and functional studies to determine whether subclinical abnormalities exist in mitochondria of blood cells from FRDA patients. Frataxin protein levels were significantly decreased in platelets and peripheral blood mononuclear cells from FRDA patients. Furthermore, the most significant differences associated with frataxin deficiency in FRDA blood cell mitochondria were the decrease of two mitochondrial heat shock proteins. We did not observe profound changes in frataxin-targeted mitochondrial proteins or mitochondrial functions or an increase of apoptosis in peripheral blood cells, suggesting that functional defects in these mitochondria are not readily apparent under resting conditions in these cells.
Collapse
Affiliation(s)
- Mary A. Selak
- Children’s Hospital of Philadelphia Research Institute, Children’s Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA, USA
| | - Elise Lyver
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Elizabeth Micklow
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Eric C. Deutsch
- Departments of Neurology and Pediatrics, University of Pennsylvania School of Medicine, and Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Özlem Önder
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Nur Selamoglu
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Claire Yager
- Children’s Hospital of Philadelphia Research Institute, Children’s Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA, USA
| | - Simon Knight
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Martin Carroll
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew Dancis
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - David R. Lynch
- Departments of Neurology and Pediatrics, University of Pennsylvania School of Medicine, and Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Jean-Emmanuel Sarry
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| |
Collapse
|
2
|
Bérczi A, Desmet F, Van Doorslaer S, Asard H. Spectral characterization of the recombinant mouse tumor suppressor 101F6 protein. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:1129-42. [PMID: 19943161 DOI: 10.1007/s00249-009-0564-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 10/29/2009] [Accepted: 11/05/2009] [Indexed: 10/20/2022]
Abstract
Tumor suppressor protein 101F6, a gene product of the 3p21.3 (human) and 9F1 (mouse) chromosomal region, has recently been identified as a member of the cytochrome b561 (Cyt-b561) protein family by sequence homology. The His(6)-tagged recombinant mouse tumor suppressor Cyt-b561 protein (TSCytb) was recently expressed in yeast and purified, and the ascorbate reducibility was determined. TSCytb is auto-oxidizable and has two distinct heme b centers with redox potentials of approximately 40 and approximately 140 mV. Its split alpha-band in the dithionite-reduced spectrum at both 295 and 77 K is well resolved, and the separation between the two alpha-peaks is approximately 7 nm (approximately 222 cm(-1)). Singular value decomposition analysis of the split alpha-band in the ascorbate-reduced spectra revealed the presence of two major spectral components, each of them with split alpha-band but with different peak separations (6 and 8 nm). Similar minor differences in peak separation were obtained when the split alpha-bands in ascorbate-reduced difference spectra at low (<1 mM) and high (>10 mM) ascorbate concentrations were analysed. According to low-temperature electron paramagnetic resonance (EPR) spectroscopy, the two heme b centers are in the low-spin ferric state with maximum principal g values of 3.61 and 2.96, respectively. These values differ from the ones observed for other members of the Cyt-b561 family. According to resonance Raman spectroscopy, the porphyrin rings are in a relaxed state. The spectroscopic results are only partially in agreement with those obtained earlier for the native chromaffin granule Cyt-b561.
Collapse
Affiliation(s)
- Alajos Bérczi
- Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, P.O. Box 521, 6701, Szeged, Hungary.
| | | | | | | |
Collapse
|
3
|
Sherratt HS, Watmough NJ, Johnson MA, Turnbull DM. Methods for study of normal and abnormal skeletal muscle mitochondria. METHODS OF BIOCHEMICAL ANALYSIS 2006; 33:243-335. [PMID: 3282151 DOI: 10.1002/9780470110546.ch6] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
4
|
Shinkarev VP, Crofts AR, Wraight CA. Spectral analysis of the bc(1) complex components in situ: beyond the traditional difference approach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1757:67-77. [PMID: 16386703 DOI: 10.1016/j.bbabio.2005.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 11/08/2005] [Accepted: 11/10/2005] [Indexed: 10/25/2022]
Abstract
The cytochrome (cyt) bc(1) complex (ubiquinol: cytochrome c oxidoreductase) is the central enzyme of mitochondrial and bacterial electron-transport chains. It is rich in prosthetic groups, many of which have significant but overlapping absorption bands in the visible spectrum. The kinetics of the cytochrome components of the bc(1) complex are traditionally followed by using the difference of absorbance changes at two or more different wavelengths. This difference-wavelength (DW) approach has been used extensively in the development and testing of the Q-cycle mechanism of the bc(1) complex in Rhodobacter sphaeroides chromatophores. However, the DW approach does not fully compensate for spectral interference from other components, which can significantly distort both amplitudes and kinetics. Mechanistic elaboration of cyt bc(1) turnover requires an approach that overcomes this limitation. Here, we compare the traditional DW approach to a least squares (LS) analysis of electron transport, based on newly determined difference spectra of all individual components of cyclic electron transport in chromatophores. Multiple sets of kinetic traces, measured at different wavelengths in the absence and presence of specific inhibitors, were analyzed by both LS and DW approaches. Comparison of the two methods showed that the DW approach did not adequately correct for the spectral overlap among the components, and was generally unreliable when amplitude changes for a component of interest were small. In particular, it was unable to correct for extraneous contributions to the amplitudes and kinetics of cyt b(L). From LS analysis of the chromophoric components (RC, c(tot), b(H) and b(L)), we show that while the Q-cycle model remains firmly grounded, quantitative reevaluation of rates, amplitudes, delays, etc., of individual components is necessary. We conclude that further exploration of mechanisms of the bc(1) complex, will require LS deconvolution for reliable measurement of the kinetics of individual components of the complex in situ.
Collapse
Affiliation(s)
- Vladimir P Shinkarev
- Department of Biochemistry, University of Illinois at Urbana -- Champaign, 156 Davenport Hall, 607 South Mathews Avenue, Urbana, IL 61801, USA.
| | | | | |
Collapse
|
5
|
|
6
|
Borisov VB, Sedelnikova SE, Poole RK, Konstantinov AA. Interaction of cytochrome bd with carbon monoxide at low and room temperatures: evidence that only a small fraction of heme b595 reacts with CO. J Biol Chem 2001; 276:22095-9. [PMID: 11283005 DOI: 10.1074/jbc.m011542200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Azotobacter vinelandii is an obligately aerobic bacterium in which aerotolerant dinitrogen fixation requires cytochrome bd. This oxidase comprises two polypeptide subunits and three hemes, but no copper, and has been studied extensively. However, there remain apparently conflicting reports on the reactivity of the high spin heme b(595) with ligands. Using purified cytochrome bd, we show that absorption changes induced by CO photodissociation from the fully reduced cytochrome bd at low temperatures demonstrate binding of the ligand with heme b(595). However, the magnitude of these changes corresponds to the reaction with CO of only about 5% of the heme. CO binding with a minor fraction of heme b(595) is also revealed at room temperature by time-resolved studies of CO recombination. The data resolve the apparent discrepancies between conclusions drawn from room and low temperature spectroscopic studies of the CO reaction with cytochrome bd. The results are consistent with the proposal that hemes b(595) and d form a diheme oxygen-reducing center with a binding capacity for a single exogenous ligand molecule that partitions between the hemes d and b(595) in accordance with their intrinsic affinities for the ligand. In this model, the affinity of heme b(595) for CO is about 20-fold lower than that of heme d.
Collapse
Affiliation(s)
- V B Borisov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | | | | | | |
Collapse
|
7
|
Rasnik I, Sharp KA, Fee JA, Vanderkooi JM. Spectral Analysis of Cytochrome c: Effect of Heme Conformation, Axial Ligand, Peripheral Substituents, and Local Electric Fields. J Phys Chem B 2000. [DOI: 10.1021/jp002656k] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ivan Rasnik
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, School of Medicine, Philadelphia Pennsylvania 19104-6059, and Department of Biology, Room 2218 Bonner Hall, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0368
| | - Kim A. Sharp
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, School of Medicine, Philadelphia Pennsylvania 19104-6059, and Department of Biology, Room 2218 Bonner Hall, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0368
| | - James A. Fee
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, School of Medicine, Philadelphia Pennsylvania 19104-6059, and Department of Biology, Room 2218 Bonner Hall, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0368
| | - Jane M. Vanderkooi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, School of Medicine, Philadelphia Pennsylvania 19104-6059, and Department of Biology, Room 2218 Bonner Hall, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0368
| |
Collapse
|
8
|
Manas ES, Wright WW, Sharp KA, Friedrich J, Vanderkooi JM. The Influence of Protein Environment on the Low Temperature Electronic Spectroscopy of Zn-Substituted Cytochrome c. J Phys Chem B 2000. [DOI: 10.1021/jp0005975] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eric S. Manas
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059, and Technische Universität München, Lehrstuhl für Physik Weihenstephan, Vöttinger Strasse 40, D-85350 Freising, Germany
| | - Wayne W. Wright
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059, and Technische Universität München, Lehrstuhl für Physik Weihenstephan, Vöttinger Strasse 40, D-85350 Freising, Germany
| | - Kim A. Sharp
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059, and Technische Universität München, Lehrstuhl für Physik Weihenstephan, Vöttinger Strasse 40, D-85350 Freising, Germany
| | - Josef Friedrich
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059, and Technische Universität München, Lehrstuhl für Physik Weihenstephan, Vöttinger Strasse 40, D-85350 Freising, Germany
| | - Jane M. Vanderkooi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059, and Technische Universität München, Lehrstuhl für Physik Weihenstephan, Vöttinger Strasse 40, D-85350 Freising, Germany
| |
Collapse
|
9
|
Manas ES, Vanderkooi JM, Sharp KA. The Effects of Protein Environment on the Low Temperature Electronic Spectroscopy of Cytochrome c and Microperoxidase-11. J Phys Chem B 1999. [DOI: 10.1021/jp9908552] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eric S. Manas
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6089
| | - Jane M. Vanderkooi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6089
| | - Kim A. Sharp
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6089
| |
Collapse
|
10
|
Penisson-Besnier I, Degoul F, Desnuelle C, Dubas F, Josi K, Emile J, Lestienne P. Uneven distribution of mitochondrial DNA mutation in MERRF dizygotic twins. J Neurol Sci 1992; 110:144-8. [PMID: 1324294 DOI: 10.1016/0022-510x(92)90021-c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A new family of myoclonic epilepsy with ragged-red fibers (MERRF) was studied at clinical, histological, biochemical and molecular genetic levels. There was a remarkable variation in the age of onset, the clinical presentation and the severity of symptoms. Multiple defects affecting respiratory chain complexes I, III and IV were detected in 2 patients. The point mutation at 8344 of the mitochondrial genome was found in all the maternal lineage with a relatively narrow range of variation in the percentage of mutant mitochondrial genomes. The one exception was represented by a set of dizygotic twins, one clinically affected and showing high proportions of mutant mitochondrial DNAs (mtDNAs) in blood cells, while the other was asymptomatic and showed very small amounts of mutant mt-DNAs in blood and skin. This could suggest an early segregation of the mitochondrial genome during ovogenesis.
Collapse
|
11
|
Bindoff LA, Birch-Machin MA, Cartlidge NE, Parker WD, Turnbull DM. Respiratory chain abnormalities in skeletal muscle from patients with Parkinson's disease. J Neurol Sci 1991; 104:203-8. [PMID: 1658241 DOI: 10.1016/0022-510x(91)90311-t] [Citation(s) in RCA: 170] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Parkinson's disease is one of the commonest neurodegenerative disorders in Western society. Although the neuropathological changes have been well documented, the underlying biochemical defect is unknown. Toxins may play a part in the aetiology of this disorder. It has been shown that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces a Parkinson-like syndrome in both man and primates and 1-methyl-4-phenylpyridine (MPP+), a metabolite of MPTP, inhibits NADH-ubiquinone oxidoreductase (complex I) of the mitochondrial respiratory chain. We studied mitochondrial respiratory chain function in skeletal muscle from patients with Parkinson's disease because, like brain, it has a high dependence on oxidative metabolism. Our results show low activity in all complexes studied (I, II and IV). The implications of these findings are discussed in relation to the aetiology of Parkinson's disease.
Collapse
Affiliation(s)
- L A Bindoff
- Division of Clinical Neuroscience, Medical School, University of Newcastle upon Tyne, U.K
| | | | | | | | | |
Collapse
|
12
|
Bindoff LA, Desnuelle C, Birch-Machin MA, Pellissier JF, Serratrice G, Dravet C, Bureau M, Howell N, Turnbull DM. Multiple defects of the mitochondrial respiratory chain in a mitochondrial encephalopathy (MERRF): a clinical, biochemical and molecular study. J Neurol Sci 1991; 102:17-24. [PMID: 1649912 DOI: 10.1016/0022-510x(91)90088-o] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We describe a young man with a progressive neurological disorder including myoclonus, mental retardation, muscle weakness and a mitochondrial myopathy (myoclonus epilepsy and ragged red fibres--MERRF). Multiple abnormalities of the mitochondrial respiratory chain in skeletal muscle are shown by direct measurement of the flux through the individual complexes, low-temperature redox spectroscopy and decreased immunodetectable subunits of complexes I and IV by immunoblotting. No abnormality of mitochondrial DNA was found. This is the first report of combined defects of complexes I, III and IV as a cause of this clinical syndrome. However, we propose that the occurrence of multiple respiratory chain defects may be more common than previously recognised and that this particular combination of defects, involving complexes I, III and IV, may be the predominant biochemical abnormality in MERRF.
Collapse
Affiliation(s)
- L A Bindoff
- Division of Clinical Neuroscience, University of Newcastle upon Tyne, Medical School, U.K
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Watmough NJ, Bindoff LA, Birch-Machin MA, Jackson S, Bartlett K, Ragan CI, Poulton J, Gardiner RM, Sherratt HS, Turnbull DM. Impaired mitochondrial beta-oxidation in a patient with an abnormality of the respiratory chain. Studies in skeletal muscle mitochondria. J Clin Invest 1990; 85:177-84. [PMID: 2153151 PMCID: PMC296403 DOI: 10.1172/jci114409] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Defects of complex I of the mitochondrial respiratory chain are important causes of neurological disease. We report studies that demonstrate a severe deficiency of complex I activity with less severe abnormalities of complexes III and IV (less than 5, 63, and 30% of control values, respectively) in a skeletal muscle mitochondrial fraction from a 22-yr-old female with weakness, lactic acidemia, and the deposition of intramuscular neutral lipid. The observation that lipid accumulates in this and other patients with complex I deficiency suggests impaired mitochondrial fatty acid oxidation. To investigate this mechanism we have shown impaired flux through beta-oxidation [( U-14C]hexadecanoate oxidation was 66% of control rate) and accumulation of specific acyl-CoA ester intermediates. The changes in fatty acid metabolism in complex I deficiency are secondary to the reduced state within the mitochondrial matrix with low NAD+/NADH ratios.
Collapse
Affiliation(s)
- N J Watmough
- Department of Clinical Neuroscience, University of Newcastle upon Tyne, England
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Cooper JM, Petty RK, Hayes DJ, Morgan-Hughes JA, Clark JB. Chronic administration of the oral hypoglycaemic agent diphenyleneiodonium to rats. An animal model of impaired oxidative phosphorylation (mitochondrial myopathy). Biochem Pharmacol 1988; 37:687-94. [PMID: 3342100 DOI: 10.1016/0006-2952(88)90143-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Daily subcutaneous administration of the oral hypoglycaemic agent, diphenyleneiodonium at a low dose (1.5 mg/kg body weight) over a 4-5 week period resulted in a normoglycaemic stable animal model of impaired oxidative phosphorylation in the rat. Diphenyleneiodonium specifically inhibits NAD-linked mitochondrial oxidation [Bloxham, Biochem. Soc. Trans. 7, 103 (1979)], and in isolated mitochondrial preparations from heart, soleus and gastrocnemius muscle and liver from treated animals NAD-linked respiration was reduced by 40% or more of mean control values. Brain and kidney mitochondria isolated from the treated group had similar rates of NAD-linked respiration to their respective control values. The activity of NADH-ferricyanide reductase was significantly reduced in all tissues tested, even in the isolated brain and kidney mitochondria where the activity in these tissues was 60-75% of control values. This suggests that at least 40% of Complex I activity must be inhibited before there is a decline in NAD-linked mitochondrial respiration. This paper discusses the use of diphenyleneiodonium as a means of establishing an animal model of the human disease state, termed mitochondrial myopathy.
Collapse
Affiliation(s)
- J M Cooper
- Department of Biochemistry, Medical College of St. Bartholomew's Hospital, University of London, U.K
| | | | | | | | | |
Collapse
|
15
|
Turnbull DM, Sherratt HS. Metabolic studies using isolated skeletal muscle: investigation of metabolic myopathies. BAILLIERE'S CLINICAL ENDOCRINOLOGY AND METABOLISM 1987; 1:967-97. [PMID: 3330437 DOI: 10.1016/s0950-351x(87)80013-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
16
|
Georgiou CD, Webster DA. Identification of b, c, and d cytochromes in the membrane of Vitreoscilla. Arch Microbiol 1987; 148:328-33. [PMID: 2825616 DOI: 10.1007/bf00456712] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cytochromes b, c, d, and o were identified by spectroscopic analysis of respiratory membrane fragments from Vitreoscilla sp., strain C1. Carbon monoxide difference spectra of the reduced membranes had absorption maxima at 416, 534, and 571 nm (ascribed to cytochrome o) and 632 nm (cytochrome d). Derivative spectra of the pyridine hemochromogen spectra of the membranes identified the presence of b- and c-type cytochromes in Vitreoscilla. The cyanide binding curve of the membranes was biphasic with dissociation constants of 2.14 mM and 10.7 which were assigned to cytochrome o and cytochrome d, respectively. Membranes bound carbon monoxide with dissociation constant 3.9 microM, which was assigned to cytochrome o. Cytochrome c556 and a NADH-p-iodonitrotetrazolium violet reductase component were partially purified from Vitreoscilla membranes.
Collapse
Affiliation(s)
- C D Georgiou
- Department of Biology, Illinois Institute of Technology, Chicago 60616
| | | |
Collapse
|
17
|
Selak MA, Scandella CJ. Respiration capacity of mitochondria isolated from unfertilized and fertilized sea urchin eggs. Exp Cell Res 1987; 169:369-78. [PMID: 3556423 DOI: 10.1016/0014-4827(87)90197-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mitochondria were isolated from unfertilized and fertilized eggs of the sea urchin, Strongylocentrotus purpuratus. Both preparations exhibited coupled adenosine 5'-diphosphate (ADP)-dependent) oxidation of flavin and pyridine-linked substrates and both yielded the expected P:O ratios with these substrates. Highest respiratory control indices (greater than 4.0) were observed when succinate or pyruvate + malate were used as substrates. Mitochondria from unfertilized and fertilized eggs exhibited sensitivity to respiratory and phosphorylation inhibitors and uncouplers and both preparations exhibited cross-over points at sites I, II and III of the respiratory chain. Low-temperature difference spectra revealed a normal complement of cytochromes c, b and aa3, although cytochrome c from unfertilized eggs appears to be more subject to extraction during the course of mitochondrial isolation than does cytochrome c from fertilized eggs. An unidentified pigment absorbing at approx. 570 nm was visible in low-temperature spectra of unfertilized eggs and unfertilized egg mitochondria.
Collapse
|
18
|
Hayes DJ, Hilton-Jones D, Arnold DL, Galloway G, Styles P, Duncan J, Radda GK. A mitochondrial encephalomyopathy. A combined 31P magnetic resonance and biochemical investigation. J Neurol Sci 1985; 71:105-18. [PMID: 4087016 DOI: 10.1016/0022-510x(85)90040-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A 15-year-old girl presented with recurrent encephalopathic episodes, epilepsy, myopathy and chronic lactic acidosis. A muscle biopsy revealed the presence of ragged red fibres and mitochondria with paracrystalline inclusions. Biochemical studies on freshly isolated skeletal muscle mitochondria demonstrated a deficiency of NADH-CoQ reductase activity. Investigation of her gastrocnemius muscle at rest by phosphorus nuclear magnetic resonance displayed a reduced phosphocreatine concentration with elevated levels of inorganic phosphate and ADP. Abnormalities were also apparent in her brain spectrum. It is therefore possible that the mitochondrial defect present in skeletal muscle is also being expressed in the brain.
Collapse
|
19
|
10 The Analysis of Cytochromes. METHODS IN MICROBIOLOGY 1985. [DOI: 10.1016/s0580-9517(08)70479-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
20
|
Vincent JC, Kumar C, Chance B. Quantitative visible spectroscopy at low temperatures: a systematic examination. Anal Biochem 1982; 126:86-93. [PMID: 6295211 DOI: 10.1016/0003-2697(82)90112-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
21
|
Selak MA, Conover TE. Cytochrome changes in control and concanavalin A-stimulated lymphocytes. Arch Biochem Biophys 1982; 213:306-17. [PMID: 6277254 DOI: 10.1016/0003-9861(82)90467-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
22
|
Kinnula VL, Hassinen IE. Effects of hypoxia and fasting on the cytochrome concentration in intestinal epithelial villous cell mitochondria. Role of changes in the life-span of the cells. ACTA PHYSIOLOGICA SCANDINAVICA 1981; 112:387-93. [PMID: 7315420 DOI: 10.1111/j.1748-1716.1981.tb06834.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The effects of hypoxia in vivo (40.8 kPa barometric pressure up to 120 h) and fasting on the characteristics of intestinal epithelial villous cell mitochondria and the turnover of epithelial villous cells and mitochondria were studied in rats. Using cells and mitochondria isolated in the isotonic mannitol medium, it was found that 24-h hypoxia or fasting did not alter the mitochondrial cytochrome content, but 48-h hypoxia or fasting led to increases of 70% and 37% in the cytochrome aa3 concentration in the hypoxic and fasting animals respectively. The turnover of intestinal epithelial cells was studied by observing the labelling kinetics of the cells with 3H-thymidine and the turnover of the cell and mitochondrial proteins with (guanido-14C)-arginine or 3H-leucine. The decay in thymidine radioactivity obeyed exponential kinetics from which half-lives of 1.15, 1.31 and 1.53 days were calculated in the control, fasting and hypoxic animals respectively. The half-lives for total cellular protein were 1.31, 1.54 and 1.54 days respectively when calculated from the (guanido-14C)-arginine experiments, or 0.69, 0.75 and 0.99 days when calculated from the leucine experiments. The labelling experiments with (guanido-14C)-arginine indicated that the turnover of mitochondrial proteins in intestinal epithelial cells is the same as that of the cells themselves. Since the turnover of mitochondrial proteins in other tissues is shown to be a relatively slow process, the increase in the cytochrome concentration in the intestinal cells of the hypoxic rats must be due to the longer life of the cells, which allows for the synthesis of larger amounts of the mitochondrial components.
Collapse
|
23
|
Land JM, Morgan-Hughes JA, Clark JB. Mitochondrial myopathy. Biochemical studies revealing a deficiency of NADH--cytochrome b reductase activity. J Neurol Sci 1981; 50:1-13. [PMID: 7229653 DOI: 10.1016/0022-510x(81)90038-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This paper presents biochemical data upon a young male with a mitochondrial myopathy characterised by weakness, severe exercise intolerance, muscle wasting and exercise-induced lactic acidaemia. Two similar cases have been previously documented (Morgan-Hughes et al. 1979). This report more precisely locates the mitochondrial defect. In vitro mitochondrial studies show markedly decreased respiratory rates with all NAD-linked substrates whilst that with flavin-linked succinate is normal. Oxidative phosphorylation is normally coupled. Mitochondrial cytochrome components as determined by low temperature spectroscopy are normal. NADH-ferricyanide reductase and primary dehydrogenase activities are present at levels far in excess of that required to support normal NAD-linked substrate oxidation rates. Intramitochondrial NAD levels are similar to those found in other mammalian muscle. It is proposed therefore that the mitochondrial defect is situated between NADH dehydrogenase and the CoQ--Cytochrome b complex; possibly being a derangement of a non-haem iron sulphur centre.
Collapse
|
24
|
Faller AH, Götz F, Schleifer KH. Cytochrome-patterns of Staphylococci and Micrococci and their taxonomic implications. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/s0172-5564(80)80014-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
25
|
Morgan-Hughes JA, Darveniza P, Landon DN, Land JM, Clark JB. A mitochondrial myopathy with a deficiency of respiratory chain NADH-CoQ reductase activity. J Neurol Sci 1979; 43:27-46. [PMID: 521828 DOI: 10.1016/0022-510x(79)90071-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This paper presents data on two sisters with a mitochondrial myopathy characterised by weakness, marked exercise intolerance and a fluctuating lactic acidaemia. Both patients also experienced episodes of increased weakness which could be brought on by unaccustomed activity, going without food or by taking small quantities of alcohol. Metabolic studies during exercise showed a marked and sudden rise in blood lactate and pyruvate levels. Biochemical studies in one case showed that mitochondrial respiratory rates were markedly decreased with all NAD-linked substrates tested but were normal with succinate and with TMPD + ascorbate. The mitochondrial cytochrome components were normal as determined by low temperature spectroscopy and the addition of uncoupler did not enhance state 3 respiratory rates utilising NAD-linked substrates. It was concluded, therefore, that the mitochondrial lesion was located at the level of the NADH-CoQ reductase complex.
Collapse
|
26
|
Booth RF, Clark JB. A rapid method for the preparation of relatively pure metabolically competent synaptosomes from rat brain. Biochem J 1978; 176:365-70. [PMID: 743245 PMCID: PMC1186243 DOI: 10.1042/bj1760365] [Citation(s) in RCA: 388] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A rapid (less than 2h) method is described for the preparation of synaptosomes from rat brain by using a discontinuous Ficoll/sucrose gradient by a flotation technique. These synaptosomes are metabolically active and minimally (less than 5%) contaminated with 'free' mitochondria as judged by marker-enzyme assays and electron microscopy.
Collapse
|
27
|
Andrews S, Cox GB, Gibson F. The anaerobic oxidation of dihydroorotate by Escherichia coli K-12. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 462:153-60. [PMID: 199252 DOI: 10.1016/0005-2728(77)90197-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The oxidation of dihydroorotate under anaerobic conditions has been examined using various mutant strains of Escherichia coli K-12. This oxidation in cells grown anaerobically in a glucose minimal medium is linked via menaquinone to the fumarate reductase enzyme coded for by the frd gene and is independent of the cytochromes. The same dihydroorotate dehydrogenase protein functions in both the anaerobic and aerobic oxidation of dihydroorotate. Ferricyanide can act as an artificial electron acceptor for dihydroorotate dehydrogenase and the dihydroorotate-menaquinone-ferricyanide reductase activity can be solubilised by 2 M guanidine-HCl with little loss of activity.
Collapse
|
28
|
Sato N, Hagihara B, Kamada T, Abe H. A sensitive method for the quantitative estimation of cytochromes a and a3 in tissues. Anal Biochem 1976; 74:105-17. [PMID: 962064 DOI: 10.1016/0003-2697(76)90313-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
29
|
Pudek MR, Bragg PD. Redox potentials of the cytochromes in the respiratory chain of aerobically grown Escherichia coli. Arch Biochem Biophys 1976; 174:546-52. [PMID: 779660 DOI: 10.1016/0003-9861(76)90382-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
30
|
Wood PM, Bendall DS. The reduction of plastocyanin by plastoquinol-1 in the presence of chloroplasts. A dark electron transfer reaction involving components between the two photosystems. EUROPEAN JOURNAL OF BIOCHEMISTRY 1976; 61:337-44. [PMID: 174911 DOI: 10.1111/j.1432-1033.1976.tb10027.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The reduction of plastocyanin by plastoquinol-1 was efficiently catalysed by disrupted chloroplasts or etioplasts in the dark. The reaction was inhibited by 2,5-dibromomethylisopropyl-p-benzo-quinone which inhibits photosynthetic electron transport between plastoquinone and cytochrome f. Evidence is presented that the reduction took place via cytochrome f, and that plastoquinone-9 was not involved. Triton X-100 and organic solvents were inhibitory, but partial fractionation was achieved without loss of activity by density gradient centrifugation in the presence of high digitonin concentrations. All active material contained cytochromes b-559LP and b-563 in addition to cytochrome f, but these b-type cytochromes were not directly involved. Other 1-electron acceptors could be used in place of plastocyanin, for instance ferricyanide and Pseudomonas cytochrome c-551. The reaction can be applied to give a sensitive dark assay for active cytochrome f. It is suggested that cytochrome f possesses two sites for interaction with redox reagents: a hydrophilic site with which plastocyanin reacts by electron transfer and a hydrophobic site with which plastoquinol reacts by hydrogen atom transfer.
Collapse
|
31
|
|
32
|
Bartelink AK, de Kort CA, Kroon AM. Mitochondrial formation in the developing flight muscles of the Colorado beetle. Dev Biol 1975; 42:262-73. [PMID: 163774 DOI: 10.1016/0012-1606(75)90333-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
33
|
Grunewald WA, Lübbers DW. [Determination of intracapillary HbO2 saturation with a cryo-microphotometric method, applied to the rabbit myocardium (author's transl)]. Pflugers Arch 1975; 353:255-73. [PMID: 1091914 DOI: 10.1007/bf00584288] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We succeeded in determining the O2 saturation of Hb in capillaries of the rabbit myocardium with a cryo-microphotometric method. Myocardial samples (2-3 mm) were removed in situ with a pair of nitrogin-cooled copper tongs, and rapidly frozen in Freon 13. The samples were sectioned into 10-12 mum slices in a cryotome at about minus 60 degrees C. Hemoglobin absorption spectra were measured on the capillary sections of the frozen slices at minus 100 degrees C in a vacumm-isolated microscope cooling chamber which we developed for the UMSP 1 (C. Zeiss, Oberkochen). The spectra were subdivided into three basic components (oxygenated Hb, desoxygenated Gb, and desoxygenated dehydrated Hb) with a weighted multi-component analysis (Lübbers and Wodick, 1969). The basic components were measured in Hb solutions. The accuracy of the method was tested both with Hb solutions inserted into glass capillaries, and Hb droplets. O2 saturations of the Hb solutions were measured at room temperature. Subsequently, both test solutions were frozen, HbO2 saturation measured in the glass capillaries at low temperatures agreed well with those recorded at room temperature. HbO2 saturation of the sectioned hemoglobin droplets was found to be systematically increased with low Hb32 saturations as compared with the records made at room temperature. The systematic error was determined and the intracapillary HbO2 saturations were corrected accordingly. Measurements on samples of the rabbit myocardium showed that the histogram of capillary HbO2 saturations has a maximum at saturations of 20-30%. The lowest saturation values were found to be between 0 and 10%, but these values were recorded less frequently. The arterial HbO2 saturation in the femoral artery was about 98%.
Collapse
|
34
|
Huang CH, Keyhani E, Lee CP. Fractionation by sucrose density gradient centrifugation of membrane fragments derived by sonic disruption of beef heart mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 305:455-73. [PMID: 4147458 DOI: 10.1016/0005-2728(73)90191-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
35
|
Keyhani J, Keyhani E, Goodgal SH. Studies on the cytochrome content of Phycomyces spores during germination. EUROPEAN JOURNAL OF BIOCHEMISTRY 1972; 27:527-34. [PMID: 5050661 DOI: 10.1111/j.1432-1033.1972.tb01869.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
36
|
|
37
|
Shipp WS, Piotrowski M, Friedman AE. Apparent cytochrome gene dose effects in F-lac and F-gal heterogenotes of Escherichia coli. Arch Biochem Biophys 1972; 150:473-81. [PMID: 4557889 DOI: 10.1016/0003-9861(72)90064-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
38
|
Dutton PL, Erecinska M, Sato N, Mukai Y, Pring M, Wilson DF. Reactions of b-cytochromes with ATP and antimycin A in pigeon heart mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 267:15-24. [PMID: 5019472 DOI: 10.1016/0005-2728(72)90134-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
39
|
Wohlrab H, Degn H. Retarded reduction of cytochrome b 5 following the aerobic-anaerobic transition of intact rat liver mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 256:216-22. [PMID: 4335835 DOI: 10.1016/0005-2728(72)90054-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
40
|
Shipp WS. Multiple b cytochromes in rat and pigeon mitochondria detected by finite difference analysis of absorption spectra. Biochem Biophys Res Commun 1971; 45:1437-43. [PMID: 5128189 DOI: 10.1016/0006-291x(71)90181-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
41
|
Keyhani E, Chance B. Cytochrome biosynthesis under copper-limited conditions in Candida utilis. FEBS Lett 1971; 17:127-132. [PMID: 11946013 DOI: 10.1016/0014-5793(71)80580-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ezzatollah Keyhani
- Johnson Research Foundation, University of Pennsylvania,0 19106, Philadelphia, Pennsylvania, USA
| | | |
Collapse
|
42
|
|
43
|
Fleischer S, Fleischer B, Azzi A, Chance B. Cytochrome b5 and P-450 in liver cell fractions. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 225:194-200. [PMID: 4324133 DOI: 10.1016/0005-2736(71)90212-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
44
|
|
45
|
Cheah KS, Chance B. The oxidase systems of Ascaris-muscle mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 223:55-60. [PMID: 4320757 DOI: 10.1016/0005-2728(70)90131-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
46
|
|
47
|
Hendler RW, Nanninga N. Respiration and protein synthesis in Escherichia coli membrane-envelope fragments. 3. Electron microscopy and analysis of the cytochromes. J Biophys Biochem Cytol 1970; 46:114-29. [PMID: 4394073 PMCID: PMC2108062 DOI: 10.1083/jcb.46.1.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The membranous nature of pellets obtained from broken Escherichia coli spheroplasts by successive centrifugation at 3500 g (P(1)), 20,000 g (P(2)), and 105,000 g (P(3)), has been established by electron microscopy. Spectrophotometric analysis has shown that about 90% of the cytochromes are concentrated in the particulate fractions. The crude ribosomal pellet (P(3)) contained as much of the total cytochromes as did the pellet obtained at 20,000 g (P(2)). The high cytochrome content of P(3) is consistent with its high oxidative activity (1) and the presence of membrane vesicles in this fraction. Analysis at 77 degrees K intensified the optical extinction of all the cytochrome absorption bands, but the degree of intensification was not uniform for each fraction nor for each band within a given fraction. Carbon monoxide had little or no inhibiting effect on NADH oxidation. Reduced plus carbon monoxide difference spectra yielded artifactual absorption bands in the wave length regions where reduced vs. oxidized absorption bands normally occur. Succinate and NADH, either together or separately, reduced nearly all of the cytochromes, indicating that the cytochrome portion of the electron-transport chain is shared by both substrates. A tentative formulation of the electron-transport chain is presented.
Collapse
|
48
|
|
49
|
Conover TE. On the occurrence of respiratory components in calf thymus nuclei. I. Low-temperature spectra. Arch Biochem Biophys 1970; 136:541-50. [PMID: 5435443 DOI: 10.1016/0003-9861(70)90226-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
50
|
Spectroscopic Evidence for the Control of Respiration Prior to Phosphorylation in Hamster Brown Fat Cells. J Biol Chem 1970. [DOI: 10.1016/s0021-9258(18)63403-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|