To see the other types of publications on this topic, follow the link: Cytochrom b.
Journal articles on the topic 'Cytochrom b'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Cytochrom b.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Ortega, José María, Manuel Hervás, and Manuel Losada. "Isolation and Comparison of Molecular Properties of Cytochrome £-559 from Both Spinach Thylakoids and PS II Particles." Zeitschrift für Naturforschung C 44, no. 5-6 (June 1, 1989): 415–22. http://dx.doi.org/10.1515/znc-1989-5-613.
Full textAbstract:
Abstract Cytochrome b-559. Spinach Thylakoids. PS II Particles. High and Low Potential. Interconvertible Forms Cytochrome b-559 has been purified from both spinach (Spinacia oleracea L.) thylakoids and photosystem II particles in order to compare some of its more polemic molecular properties. In the two cases, cytochrome 6-559 (which is initially present in its reduced high-potential form and in its oxidized low-potential form) is purified as a single species by preparative disc electrophoresis in Triton-containing polyacrylamide gel, the isolated protein exhibiting similar molecular mass and almost identical low midpoint redox potential and absorption spectra. Moreover, sodium dodecyl sulfate polyacrylamide gel electrophoresis of the purified cytochrom e b-559 reveals, again in both cases, only one polypeptide band of similar molecular mass. Integration o f the isolated low-potential form into liposomes partly restores the high-potential form. These data corroborate our previous results and indicate that there exists in thylakoids only a cytochrome b -559 molecular species tightly bound to PS II and that the two naturally occurring low-and high-potential couples are physiological and correspond to interconvertible states of the genuine hem e protein.
2
Besch, Dorothea, Bernd Wissinger, Eberhardt Zrenner, and Beate Leo-Kotter. "Ein Fall von Leberscher Optikusneuropathie (LHON) mit einer neuen Punktmutation im Cytochrom-b-Gen." Der Ophthalmologe 97, no. 1 (January 27, 2000): 27–32. http://dx.doi.org/10.1007/pl00007105.
Full text
3
Szczepaniak, A., M. T. Black, and W. A. Cramer. "Topography of the Chloroplast Cytochrome b6: Orientation of the Cytochrome and Accessibility of the Lumen-Side Interhelix Loops." Zeitschrift für Naturforschung C 44, no. 5-6 (June 1, 1989): 453–61. http://dx.doi.org/10.1515/znc-1989-5-619.
Full textAbstract:
Abstract The to pography of chloroplast cytochromes f and b6 was probed with proteases carboxypeptidase A (CpA ), trypsin, and Staph, aureus V8. The cytochrome and its proteolytic products were detected by heme stain and, in most experiments, by immunoreaction. In thylakoids, the only protease that significantly affected the intactness of cytochrome f was CpA that caused a small (ΔMr = -1 - 2000) decrease in the apparent molecular weight. In SDS -treated thylakoids, both trypsin and V8 degraded cytochrome f. The inferred topography of cytochrom f , with the COOH -terminus on the stromal (n) side, one membrane-spanning a-helix n ear the COOH-terminus, and most of the Cyt f mass on the lumen (p) side, is consistent with that previously inferred by others. Cytochrome b6 was not sensitive to CpA . but was more sensitive to trypsin and V8 protease than cytochrome f , cytochrome b-559, or the 17 kDa OEC extrinsic protein. Trypsin caused a small decrease in size of cytochrome b6, which was observed using whole protein antibody as a single smaller band (ΔMr ≈ 2000) or two smaller discrete bands (ΔMr = -1000 and 2500, respectively) which, unlike the untreated protein , did not react with antibody generated to a peptide mimicking A sp-5 -Gln-14 near the NH2-terminus. These shorten ed tryptic fragments were attributed to cleavage after R-10 and K-23 n ear the NH2-terminus, implying an orientation with the NH2-terminus on the stromal side of the membrane. The sensitivity of cytochrome b6 toward this trypsin cleavage was increased if the membranes were first incubated with CpA , showing that the NH2 -terminal region of cytochrome b6 is masked by the COOH -terminal domain of one or more thylakoid proteins. Under conditions where degradation of cytochrome b-559, cytochrome f, or the 17 kDa OEC extrinsic protein on the lumen side of the membrane was small ( < 10-20% ). V8 protease degraded 80-90% of cytochrome b6. The main polypeptide fragment generated by V8 protease had an apparent molecular weight Mr = 16,000, reacted with antibody to a peptide mimicking Ala-146-Asp-155, and was more pronounced in membranes treated with SDS. The fragment could then result from cleavage at two sites, Glu-74 and /or Glu-166. It is concluded that the loop of cytochrome b6 protruding from the lumen side of the membrane between helices III and IV , and possibly that between helices I and II as w ell, contains a single Glu residue conferring a sensitivity to V8 protease greater than that of the lumen-side mass of cytochrome f which has many more Glu residues. This implies a lumen-skeletal structure in which one or two loops of cytochrome b6 on the lumen side are more exposed to the aqueous phase than cytochrome f.
4
Wiesemann, Frank, Ralf Wonnemann, Bernt Krebs, Heike Keutel, and Ernst-G. Jäger. "Orientierungswechsel axialer Imidazolliganden in einem Cytochrom-b-Modellkomplex in Abhängigkeit von der Oxidationsstufe des Metallzentrums." Angewandte Chemie 106, no. 13 (July 4, 1994): 1424–26. http://dx.doi.org/10.1002/ange.19941061313.
Full text
5
Zimmermann, Stefanie, R. Zehner, and A. Herzog. "Cytochrom b-Sequenz-Vergleiche zwischen Wisent(Bison bison bonasus) und Hausrind(Bos primigenius f. taurus)." Zeitschrift für Jagdwissenschaft 44, no. 1 (March 1998): 26–32. http://dx.doi.org/10.1007/bf02239881.
Full text
6
Buntin, Kathrin, Shwan Rachid, Maren Scharfe, Helmut Blöcker, Kira J Weissman, and Rolf Müller. "Produktion der Isochromanon-Antimykotika Ajudazol A und B inChondromyces crocatus Cm c5: Biosynthesemaschinerie und Cytochrom-P450-Modifikationen." Angewandte Chemie 120, no. 24 (June 2, 2008): 4671–76. http://dx.doi.org/10.1002/ange.200705569.
Full text
7
Yamada, Mitsunori, Kaoru Nakasone, Hideyuki Tamegai, Chiaki Kato, Ron Usami, and Koki Horikoshi. "Pressure Regulation of Soluble Cytochromesc in a Deep-Sea Piezophilic Bacterium,Shewanella violacea." Journal of Bacteriology 182, no. 10 (May 15, 2000): 2945–52. http://dx.doi.org/10.1128/jb.182.10.2945-2952.2000.
Full textAbstract:
ABSTRACT Two c-type cytochromes from the soluble fraction of a deep-sea moderately piezophilic bacterium, Shewanella violacea, were purified and characterized, and the genes coding for these cytochromes were cloned and sequenced. One of the cytochromes, designated cytochrome c A, was found to have a molecular mass of approximately 8.3 kDa, and it contained one heme c per molecule. The other, designated cytochrome c B, was found to have a molecular mass of approximately 23 kDa, and it contained two heme cmolecules per protein molecule. The amount of cytochromec B expressed in cells grown at high hydrostatic pressure (50 MPa) was less than that in cells grown at atmospheric pressure, whereas cytochrome c A was constitutively expressed under all pressure conditions examined. The results of Northern blotting analysis were consistent with the above-mentioned observations and suggested that the pressure regulation of cytochrome c B gene expression occurred at the transcriptional level. These results suggest that the components of the respiratory chain of moderately piezophilic S. violaceacould be exchanged according to the growth pressure conditions.
8
Stüber, Frank, and Ulrike Stamer. "Pharmakogenetik und pädiatrische Schmerztherapie." Kinder- und Jugendmedizin 4, no. 05 (2004): 161–67. http://dx.doi.org/10.1055/s-0037-1617830.
Full textAbstract:
ZusammenfassungNeue Erkenntnisse über die Struktur des Genoms und die Entdeckung genomischer Varianten haben die genetische Diagnostik sowohl für komplexe und akute Erkrankungen als auch für den Bereich Pharmakogenetik interessant werden lassen.Für einige Bereiche, z. B. der großen Gruppe der metabolisierenden Enzyme, liegen schon Untersuchungen vor, die zeigen, dass genetische Varianten einen Einfluss auf Effektivität und Nebenwirkungen von Arzneimitteln haben. So erfahren Patienten mit einer Defizienz für das Cytochrom P450-Isoenzym 2D6 keine oder nur eine reduzierte Analgesie durch Codein und Tramadol. Auch für die Wirksamkeit und die Nebenwirkungen von Nichtopioid-Analgetika können genetische Varianten eine Rolle spielen.Erkenntnisse aus dem Bereich der Pharmakogenetik werden es in Zukunft erlauben, die Therapie der individuellen (genetischen) Konstellation anzupassen.
9
Saribas, A. Sami, Sevnur Mandaci, and Fevzi Daldal. "An Engineered Cytochromeb6c1 Complex with a Split Cytochrome b Is Able To Support Photosynthetic Growth of Rhodobacter capsulatus." Journal of Bacteriology 181, no. 17 (September 1, 1999): 5365–72. http://dx.doi.org/10.1128/jb.181.17.5365-5372.1999.
Full textAbstract:
ABSTRACT The ubihydroquinone-cytochrome c oxidoreductase (or the cytochrome bc 1 complex) fromRhodobacter capsulatus is composed of the Fe-S protein, cytochrome b, and cytochromec 1 subunits encoded bypetA(fbcF), petB(fbcB), and petC(fbcC) genes organized as an operon. In the work reported here, petB(fbcB) was split genetically into two cistrons, petB6 andpetBIV, which encoded two polypeptides corresponding to the four amino-terminal and four carboxyl-terminal transmembrane helices of cytochrome b, respectively. These polypeptides resembled the cytochromeb 6 and su IV subunits of chloroplast cytochromeb 6 f complexes, and together with the unmodified subunits of the cytochromebc 1 complex, they formed a novel enzyme, named cytochrome b 6 c 1complex. This membrane-bound multisubunit complex was functional, and despite its smaller amount, it was able to support the photosynthetic growth of R. capsulatus. Upon further mutagenesis, a mutant overproducing it, due to a C-to-T transition at the second base of the second codon of petBIV, was obtained. Biochemical analyses, including electron paramagnetic spectroscopy, with this mutant revealed that the properties of the cytochromeb 6 c 1 complex were similar to those of the cytochrome bc 1 complex. In particular, it was highly sensitive to inhibitors of the cytochrome bc 1 complex, including antimycin A, and the redox properties of its b- and c-type heme prosthetic groups were unchanged. However, the optical absorption spectrum of its cytochrome b L heme was modified in a way reminiscent of that of a cytochromeb 6 f complex. Based on the work described here and that with Rhodobacter sphaeroides (R. Kuras, M. Guergova-Kuras, and A. R. Crofts, Biochemistry 37:16280–16288, 1998), it appears that neither the inhibitor resistance nor the redox potential differences observed between the bacterial (or mitochondrial) cytochromebc 1 complexes and the chloroplast cytochromeb 6 f complexes are direct consequences of splitting cytochrome b into two separate polypeptides. The overall findings also illustrate the possible evolutionary relationships among various cytochrome bcoxidoreductases.
10
Buntin, Kathrin, Shwan Rachid, Maren Scharfe, Helmut Blöcker, Kira J Weissman, and Rolf Müller. "Produktion der Isochromanon-Antimykotika Ajudazol A und B in Chondromyces crocatus Cm c5: Biosynthesemaschinerie und Cytochrom-P450-Modifikationen." Angewandte Chemie 121, no. 52 (December 15, 2009): 9957. http://dx.doi.org/10.1002/ange.200990260.
Full text
11
Zimmermann, Stefanie, R. Zehner, and A. Herzog. "Cytochrom b-Sequenz-Vergleiche zwischen Rothirsch(Cervus elaphus hippelaphus), Damhirsch(Dama dama dama) und Reh(Capreolus capreolus capreolus)." Zeitschrift für Jagdwissenschaft 44, no. 1 (March 1998): 16–25. http://dx.doi.org/10.1007/bf02239880.
Full text
12
Eckert, Anne. "Spezielle Arzneimittelinteraktionen." Therapeutische Umschau 66, no. 6 (June 1, 2009): 485–92. http://dx.doi.org/10.1024/0040-5930.66.6.485.
Full textAbstract:
Aufgrund der häufig vorliegenden internistischen Komorbidität bei psychiatrischen Patienten, aber auch der Notwendigkeit einer Kombinationstherapie mit anderen Psychopharmaka wie z. B. die Kombination von Antidepressiva mit Benzodiazepinen oder Neuroleptika bei Vorliegen einer bestimmten Indikationsstellung bzw. Therapieresistenz, treten Interaktionen, die den Metabolismus der einzelnen Substanzen beeinflussen, sehr häufig auf und führen meist zum Anstieg der unerwünschten Arzneimittelwirkungen. Aufgrund unseres heutigen Wissensstandes über die wichtigen am hepatischen Arzneimittelmetabolismus beteiligten Cytochrom-P450-Isoenzyme sind solche Interaktionen häufig vorhersagbar, und mit der vorherigen Wahl des geeigneten, an die individuelle Situation und Begleitmedikation des Patienten angepassten Medikamentes vermeidbar. Im vorliegenden Beitrag werden daher medikamentöse Wechselwirkungen von Psychopharmaka vorgestellt unter besonderer Berücksichtigung von Substanzen aus der Gruppe der Antidepressiva der zweiten Generation (SSRI’s), neuerer Antidepressiva (SNRI’s: Venlafaxin and Duloxetin; Bupropion, Mirtazapin, Trazodon), neuer atypischer Antidepressiva (Agomelatin) und atypischen Antipsychotika der neuen Generation (Aripiprazol, Paliperidon).
13
Moskalenko, Andrei A., and Nina Yu Kuznetsova. "Effect of trypsin on D1/D2-cytochrom b 559 Photosystem 2 reaction center complex and reaction center from Rhodopseudomonas viridis." Photosynthesis Research 35, no. 3 (March 1993): 227–34. http://dx.doi.org/10.1007/bf00016554.
Full text
14
Sedlák, P., R. Vávra, P. Vejl, S. Boček, and J. Kloutvorová. "Efficacy loss of strobilurins used in protection against apple scab in Czech orchards." Horticultural Science 40, No. 2 (May 23, 2013): 45–51. http://dx.doi.org/10.17221/22/2013-hortsci.
Full textAbstract:
The apple scab caused by Venturia inaequalis is important apple disease in temperate zone. Economical losses caused by the pathogen are effectively reduced by intensive chemical protection and breeding. Occurrences of pathogen resistence to strobilurin fungicides were noted in some Czech orchards in the past. In 2007–2011, collection of 136 isolates V. inaequalis was tested with the aim to detect presence of single-point mutations of cytochrom b (cytb) gene causing efficacy loss of strobilurins. Consequently occurrence of beta-tubulin (beta-tub) gene mutation causing resistance to benomyl was studied with the aim to obtain comparative data about frequency of mutation in non-selective environment. Therefore simple and highly repeatable PCR based mutation detecting methods were optimised. Analysis brought knowledge about high similarity of cytb and beta-tub genes mutations occurrence. Whilst the frequency of the G143A substitution in cytb gene was 65% the E198A substitution of beta-tub gene occurred in 54% within pathogen population. This high frequency of resistant population necessitates revision of the way of strobilurins use in apple scab management.
15
Piantadosi, C. A., A. L. Sylvia, and F. F. Jobsis-Vandervliet. "Differences in brain cytochrome responses to carbon monoxide and cyanide in vivo." Journal of Applied Physiology 62, no. 3 (March 1, 1987): 1277–84. http://dx.doi.org/10.1152/jappl.1987.62.3.1277.
Full textAbstract:
Cytochrome oxidation-reduction responses to two mitochondrial electron transport inhibitors, carbon monoxide (CO) and cyanide (CN), were studied in the intact brains of fluorocarbon-circulated rats. In vivo reflectance spectrophotometry indicated that cortical b-type cytochromes (564 nm) were highly resistant to reduction by CN in the presence of O2 but showed reduction responses to the administration of 1–5% CO in 90% O2. In contrast, cyanide-sensitive cytochromes aa3 (605 nm) and c + c1 (551 nm) did not increase their reduction levels during exposure to 5% CO in 90% O2. The in vivo CO-mediated b-cytochrome reduction responses did not occur after pretreatment with the cytochrome b inhibitor, antimycin A. Transmission spectrophotometry of superfused hemoglobin-free rat brain slices confirmed cortical b-type cytochromes to be CN-resistant in the presence of O2. Another cytochrome absorbing at 445 nm also was resistant to reduction by 1-mM cyanide in vitro, but it could be reduced anaerobically. The reduced 445-nm cytochrome bound CO in the presence of cyanide. We postulate that this CN-resistant CO binding component might account for in vivo cytochrome aa3-CO interactions and directly or indirectly modulate cytochrome b reduction responses to CO. In any event, the spectral data indicate different primary tissue target sites for CO and CN in living rat brain and also suggest different bioenergetic consequences of exposure to the two agents.
16
Lalande, Roger, and Roger Knowles. "Cytochrome content in Azospirillum brasilense Sp 7 grown under aerobic and denitrifying conditions." Canadian Journal of Microbiology 33, no. 2 (February 1, 1987): 151–56. http://dx.doi.org/10.1139/m87-026.
Full textAbstract:
Azospirillum brasilense Sp 7 was grown in batch cultures with O2, [Formula: see text], [Formula: see text], or N2O as final electron acceptor. There were marked differences in cytochrome composition depending on the O2 status of the culture and the electron acceptor utilized. Highly aerated cultures showed no [Formula: see text] reduction and the cytochrome composition (a soluble c-type and particulate aa3, b, and c cytochromes) was not affected by the presence of[Formula: see text]. Under low aeration, in the presence of [Formula: see text], nitrate reductase activity occurred and there was a significant increase in the soluble and particulate cytochromes. Particulate cytochrome b-556 was observed only under high aeration and the cytochrome aa3, observed under both high and low aeration, decreased as the O2 concentration decreased. A particulate CO-binding cytochrome of type o was observed in the cells grown under high aeration. Cytochrome cd nitrite reductase was observed only in the soluble fraction of [Formula: see text]-grown cultures, which also contained the highest concentrations of the soluble cytochrome c-548 and the particulate c-551. N2O-grown cultures showed b-560 and c-551 cytochromes in the particulate and the c-548 cytochrome in the soluble fraction.
17
TABER, H. "Isolation and Properties of Cytochrome a Deficient Mutants of Bacillus subtilis." Microbiology 81, no. 2 (February 1, 2000): 435–44. http://dx.doi.org/10.1099/00221287-81-2-435.
Full textAbstract:
Summary: Three classes of cytochrome a deficient mutants of Bacillus subtilis have been isolated. These classes were defined by concentration ratios of cytochromes a, b and c relative to the parent strain, and by responses to non-fermentable substrates. The cytochrome deficiencies were not due to blocks in haem biosynthesis or to failure of the control mechanisms which alter the respiratory chain during growth of B. subtilis. Mutational loss of cytochrome a did not reduce proportionately the rate of oxygen consumption by late exponential phase cells, although exponential growth rates were generally lower than the parent strain. The cytochrome system of wild-type B. subtilis appears to contain cytochromes a (or a+a3), b, c, c1, and o. A previously unreported absorption maximum at 617 nm was discovered, which was elevated in some of the cytochrome a deficient mutants. In these mutants, a new maximum also appeared at 627 nm.
18
Paget, T. A., M. Fry, and D. Lloyd. "Haemoprotein terminal oxidases in the nematodes Nippostrongylus brasiliensis and Ascaridia galli." Biochemical Journal 256, no. 1 (November 15, 1988): 295–98. http://dx.doi.org/10.1042/bj2560295.
Full textAbstract:
1. Mitochondria isolated from the gut-dwelling nematodes Nippostrongylus brasiliensis and Ascaridia galli (muscle and gut + reproductive tissue) were examined for cytochromes, and it was observed that N. brasiliensis and A. galli muscle tissue mitochondria contained a-, b- and c-type cytochromes, but their stoichiometries were quite different (1:2:1.9 and 1:11.4:13.6 respectively); A. galli gut + reproductive-tissue mitochondria, however, only contained b and c cytochromes, in a ratio of 1:0.8. 2. CO difference spectra showed the presence of CO-reacting b-type cytochrome(s) in all three types of mitochondria; the fast-reacting species comprised 30, 44 and 39% of the total in N. brasiliensis, A. galli muscle and A. galli gut + reproductive-tissue mitochondria respectively. 3. Cytochrome aa3 was observed in N. brasiliensis mitochondria and in those from A. galli muscle, but was below the level of detectability (less than 0.005 nmol/mg of protein) for A. galli gut + reproductive-tissue mitochondria. 4. Photochemical action spectra for the reversal of CO inhibition of the endogenous respiration of whole worms (at 24 microM- and 40 microM-O2 respectively for N. brasiliensis and A. galli) gave maxima at 598 and 542-543 nm, corresponding to the alpha- and beta-absorption maxima of cytochrome aa3, and at 567 nm (b-type cytochrome) for both worms. These results suggest that cytochrome aa3 is the major functional oxidase in N. brasiliensis, whereas the CO-reacting b-type cytochrome dominates in A. galli.
19
Meier, B., A. J. Jesaitis, A. Emmendörffer, J. Roesler, and M. T. Quinn. "The cytochrome b-558 molecules involved in the fibroblast and polymorphonuclear leucocyte superoxide-generating NADPH oxidase systems are structurally and genetically distinct." Biochemical Journal 289, no. 2 (January 15, 1993): 481–86. http://dx.doi.org/10.1042/bj2890481.
Full textAbstract:
We have demonstrated that human fibroblasts can release O2-. radicals by an NADPH oxidase system that appears to be functionally similar to the phagocytic system. Further analysis of these systems, however, with respect to the low-potential b-type cytochromes involved suggests that these two O2-.-generating systems are not structurally identical. Immunoblot analysis of fibroblast membranes with six different antibodies directed against both subunits of human neutrophil cytochrome b-558 indicated that the b-type cytochrome molecules involved in these systems were not identical. None of these anti-(neutrophil cytochrome b) antibodies recognized a similar cytochrome in fibroblast membranes, suggesting that the two cytochrome species are immunologically distinct. In addition, fibroblasts obtained from a patient suffering from X-linked chronic granulomatous disease (CGD) had a normal cytochrome b-558 content compared with control fibroblast membranes, whereas the cytochrome b-558 concentration in polymorphonuclear leucocytes (PMNs) from this patient was decreased to 10% of that found in PMNs from healthy controls. Likewise, the stimulated O2-. release in PMNs from this patient was less than 10% of that in control PMNs, whereas the fibroblasts showed stimulated O2-.-release rates that were indistinguishable from those of fibroblasts obtained from healthy persons. Since the genetic mutation responsible for this type of CGD results in the absence of cytochrome b-558 in PMNs, fibroblasts should be affected in the same way if both cytochrome species were identical. These results suggest therefore that the low-potential b-type cytochromes in PMNs and fibroblasts are structurally and genetically distinct.
20
Deeudom, M., J. Rock, and J. Moir. "Organization of the respiratory chain of Neisseria meningitidis." Biochemical Society Transactions 34, no. 1 (January 20, 2006): 139–42. http://dx.doi.org/10.1042/bst0340139.
Full textAbstract:
The ability of Neisseria meningitidis to utilize both oxygen and nitrogen oxides as respiratory substrates allows it to thrive in the diverse environment of the human host. Genome analysis highlighted genes encoding a cbb3 cytochrome oxidase, the aniA nitrite reductase gene and the norB nitric oxide reductase gene. In the present study, we used myxothiazol as an inhibitor of the bc1 complex in intact cells and demonstrated that electron flow to nitrite reductase and the cytochrome oxidase, but not NO reductase, passes via the cytochrome bc1 complex. UV–visible spectrophotometry of intact cells demonstrated that oxygen oxidizes c-type and b-type cytochromes. Oxidation of cytochromes by nitrite was only seen in microaerobically precultured whole cells, and the predominant oxidizable cytochromes were b-type. These are likely to be associated with the oxidation of a b-haem-containing nitric oxide reductase. Nitrite inhibits the oxidation of cytochromes by oxygen in a nitrite reductase-independent manner, indicating that nitrite may inhibit oxidase activity directly, as well as via the intermediate of denitrification, nitric oxide.
21
Gnedenko, O. V., A. S. Ivanov, E. O. Yablokov, S. A. Usanov, D. V. Mukha, G. V. Sergeev, A. V. Kuzikov, et al. "Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes." Biomeditsinskaya Khimiya 60, no. 1 (January 2014): 17–27. http://dx.doi.org/10.18097/pbmc20146001017.
Full textAbstract:
Molecular interactions between proteins redox partners (cytochromes Р450 3А4, 3А5 and cytochrome b ) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes Р450 3А4 and 3А5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b : the microsomal ( b5mc ) and mitochondrial ( b5om ) forms of this protein, as well as with 2 “chimeric” proteins, b5(om-mc) , b5(mc-om) . Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor. Essential distinction between CYP3A4 and CYP3A5 was only observed upon their interactions with cytochrome b5om . Electroanalytical characteristics of electrodes with immobilized hemoproteins were obtained. The electrochemical analysis of CYP3A4, CYP3A5, b5mc, b5om , b5(om-mc) , and b5(mc-om) immobilized on screen printed graphite electrodes modified with membranous matrix revealed that these proteins have very close reduction potentials -0.435- -0.350 V (vs. Ag/AgCl). Cytochrome b mc was shown to be capable of stimulating the electrocatalytic activity of CYP3A4 to testosterone.
22
Rogers, M. S., G. D. Jones, G. Antonini, M. T. Wilson, and M. Brunori. "Electron transfer from Phanerochaete chrysosporium cellobiose oxidase to equine cytochrome c and Pseudomonas aeruginosa cytochrome c-551." Biochemical Journal 298, no. 2 (March 1, 1994): 329–34. http://dx.doi.org/10.1042/bj2980329.
Full textAbstract:
The electron-transfer reactions of cellobiose oxidase (CBO) have been investigated by conventional and by rapid-scan stopped-flow spectroscopy at pH 6.0. Analysis of the absorbance/time/wavelength matrix by Singular Value Decomposition (SVD) confirms earlier studies showing that cellobiose rapidly reduces the flavin group (7.7 s-1; cellobiose, 100 microM) which in turn slowly (0.2 s-1) reduces the cytochrome b moiety. In the presence of CBO, cellobiose reduces cytochromes c in a reaction that does not depend on oxygen or superoxide. The rate limit for this process is independent of the source of the cytochromes c and is identical with the rate of cytochrome b reduction. Rapid-mixing experiments show that cytochrome b may donate electrons very rapidly to either mammalian cytochrome c or bacterial cytochrome c-551. The reactions were second-order (kc = 1.75 x 10(7) M-1 x s-1; kc-551 = 4.3 x 10(6) M-1 x s-1; pH 6.0, 21 degrees C and I0.064) and strongly ionic-strength (I)-dependent: kc decreasing with I and kc-551 increasing with I. These results suggest the electron-transfer site near cytochrome b bears a significant negative charge. Equilibrium gel chromatography confirms that CBO oxidase and positively charged mammalian cytochrome c make stable complexes. These results are discussed in terms of a model suggesting an electron-transfer role for cytochrome b in vivo, possibly connected with radical-mediated cellulose breakdown.
23
Lenk, Peter, Michael Wink, and Ulrich Joger. "Phylogenetic relationships among European ratsnakes of the genus Elaphe Fitzinger based on mitochondrial DNA sequence comparisons." Amphibia-Reptilia 22, no. 3 (2001): 329–39. http://dx.doi.org/10.1163/156853801317050124.
Full textAbstract:
AbstractIn order to elucidate the phylogenetic relationships in European ratsnakes of the genus Elaphe, we analyzed a 597 bp part of the mitochondrial cytochrome b gene of eight West Eurasian and one East Asian species. Lampropeltis served as outgroup. Maximum parsimony and maximum likelihood suggest the existence of four lineages: 1) E. scalaris; 2) the E. longissima species group comprising E. longissima, E. lineata, E. situla, E. hohenackeri, and E. persica; 3) E. quatuorlineata and 4) E. dione as a sister group to 3). Elaphe scalaris is basal and shows no closer affiliation with any other analyzed species. The Middle Eastern E. persica and E. hohenackeri appear basal within the E. longissima group. Elaphe lineata differs by 8% nucleotide substitutions from E. longissima, supporting the hypothesis that both taxa represent distinct species. Elaphe situla is associated with Elaphe longissima and E. lineata. Three analyzed subspecies of E. quatuorlineata are represented by distinct haplotypes. The extent of divergence gives reason to assign species status to the taxon sauromates. Besides, we found two very distinct haplotypes within the range of E. (q.) sauromates, indicating the existence of a third, so far unidentified, species within the E. quatuorlineata complex. The East Asian E. porphyracea clusters with the E. longissima group. This, as well as comparisons with supplementary sequences of Asian Elaphe species, document the multiple origins of European Elaphe. Um die phylogenetischen Beziehungen europäischer Kletternattern der Gattung Elaphe zu erhellen, sequenzierten und analysierten wir ein 597 Nukleotide messendes Stück des mitochondrialen Cytochrom b Gens von acht west-eurasischen und einer ostasiatischen Art. Lampropeltis diente als Außengruppe. Maximum parsimony und maximum likelihood Berechnungen zeigen die Existenz von vier genetischen Linien auf: a) E. scalaris; b) die E. longissima Artengruppe mit E. longissima , E. lineata, E. situla, E. hohenackeri, und E. persica; c) E. quatuorlineata und d) E. dione als Schwestergruppe zu c). Elaphe scalaris nimmt eine basale Position ein und scheint mit keiner untersuchten Art näher verwandt zu sein. Die westasiatischen Arten E. persica und E. hohenackeri sind die Schwestergruppe zu E. longissima, E. lineata und E. situla. Elaphe lineata unterscheidet sich durch 8% Nukleotidaustausche von E. longissima, wodurch der Artstatus von E. lineata unterstützt wird. Elaphe longissima, E. lineata und E. situla bilden eine Abstammungsgemeinschaft. Auch die Haplotypen der drei untersuchten E. quatuorlineata-Unterarten unterscheiden sich so stark, daß Artstatus für das Taxon sauromates zu fordern ist. Darüberhinaus fanden wir im Gebiet von E. (q.) sauromates zwei stark unterschiedliche Haplotypen, die die Existenz einer dritten bislang unidentifizierten Art nahelegen. Die ostasiatische E. porphyracea scheint der E. longissima-Gruppe nahe zu stehen. Dies, sowie der Vergleich mit ergänzenden Sequenzdaten asiatischer Elaphe-Arten, belegt den mehrfachen Ursprung europäischer Elaphe.
24
Piantadosi, C. A. "Spectrophotometry of b-type cytochromes in rat brain in vivo and in vitro." American Journal of Physiology-Cell Physiology 256, no. 4 (April 1, 1989): C840—C848. http://dx.doi.org/10.1152/ajpcell.1989.256.4.c840.
Full textAbstract:
Terminal oxidase inhibitors such as cyanide (CN) and carbon monoxide (CO) produce different absorption changes in the intact brain, suggesting different mitochondrial responses to the inhibitors. In the present study, the nature of the cytochromes involved in CO and CN responses in vivo was investigated by low-temperature spectroscopy of rat brain, frozen in situ, and of preparations of brain homogenate and isolated mitochondria. Comparison of the spectra from different preparations at the high resolution afforded by low-temperature spectroscopy indicated that absorption responses to CO in vivo originated from mitochondrial b cytochromes. Further detailed spectral analysis of mitochondrial preparations revealed three CN-insensitive b cytochromes in nonsynaptic brain mitochondria; one cytochrome could be reduced by succinate in the presence of CN, the second could be reduced by succinate plus ATP, and the third could be reduced only by anaerobiosis. The spectral characteristics of the mitochondrial b cytochromes, when compared with spectra from CO-exposed brain tissue frozen in situ, strongly implicated the energy-dependent cytochrome b in the oxidation-reduction (redox) responses caused by CO in vivo.
25
Voloshchuk, O. N., M. M. Marchenko, and M. C. Mudrak. "The change in the structural and functional organization of the guerin's carcinoma cytochrome part of respiratory chain in tumor carriers in the conditions of preliminary low-level irradiation." Biomeditsinskaya Khimiya 58, no. 6 (2012): 684–90. http://dx.doi.org/10.18097/pbmc20125806684.
Full textAbstract:
The effect of low-level irradiation of tumor-bearing rats on the structural and functional organization of the cytochrome part of respiratory chain of mitochondria isolated from Guerin's carcinoma has been investigated.The maximal reduction in the mitochondrial cytochromes a, b and c content was observed at the terminal stage of Guerin's carcinoma. A low-level irradiation during initial stages of oncogenesis produced opposite changes in the mitochondrial cytochrome content.The possible mechanism of mitochondrial haem-containing cytochromes content reduction may be attributed to impairment in their formation caused by inhibition of the key enzyme of haem synthesis, 5-aminolevulinate synthase.The determined changes of the mitochondrial cytochromes quantitative content were accompanied by decreased activity of cytochrome oxidase. The preliminary low-level irradiation of the tumor-bearing animals produced further reduction in the cytochrome oxidase activity observed in all experimental periods.
26
Gahr, Maximilian. "Koffein, das am häufigsten konsumierte Psychostimulans: eine narrative Übersichtsarbeit." Fortschritte der Neurologie · Psychiatrie 88, no. 05 (October 14, 2019): 318–30. http://dx.doi.org/10.1055/a-0985-4236.
Full textAbstract:
ZusammenfassungKoffein ist das weltweit am häufigsten konsumierte Psychostimulans. Es ist nahezu unbeschränkt verfügbar und unterliegt in Europa keiner staatlichen Regulation. Neben seiner primären Rolle als Inhalts- oder Zusatzstoff in zahlreichen Getränken findet es auch medizinische Verwendung in der adjuvanten Schmerztherapie, bei primärem Atemstillstand bei Neugeborenen und es ist zugelassen für die kurzfristige Beseitigung von Ermüdungserscheinungen. Der Wirkmechanismus von Koffein als Psychostimulans in typischerweise aufgenommen Dosierungen basiert vermutlich in erster Linie auf einem zentralen Antagonismus von Adenosinrezeptoren (A1- und A2A-Rezeptoren), was zu einer zentralen Hemmung der Adenosin-vermittelten Reduktion der Aktivität des dopaminergen und aufsteigenden Aktivierungssystems führt. Die Metabolisierung von Koffein ist hautsächlich abhängig von Cytochrom P450 1A2, sodass Faktoren, die die Aktivität von CYP 1A2 beeinflussen (z. B. Medikamente, Schwangerschaft), erhebliche Veränderungen der pharmakokinetischen Parameter induzieren können. Koffein führt insbesondere bei Individuen mit Schlafentzug zu einer Verbesserung der Vigilanz, Aufmerksamkeit und Reaktionszeit. Zudem kann es sportliche Ausdauerleistungen und muskuläre Kraft verbessern. Intoxikationen mit Koffein sind selten, können jedoch letal verlaufen. In üblicherweise aufgenommenen Mengen gilt Koffeingebrauch als nicht gesundheitsschädlich. Koffein weist zahlreiche, jedoch nicht alle Merkmale einer Substanz mit „Abhängigkeitspotential“ auf; Entzugssyndrome nach Beendigung einer längeren Anwendung und Toleranz sind bekannt. Im DSM-5 wird die „Koffeingebrauchsstörung“ als mögliche künftige Störung, die gegenwärtig weiterer Forschung bedarf, rubriziert. Das Koffeingebrauchsmuster von Patienten sollte im Rahmen der ärztlichen Tätigkeit berücksichtigt werden.
27
BRUSCHI, Mireille, Gisèle LEROY, Jacques BONICEL, Daniel CAMPESE, and Alain DOLLA. "The cytochrome c3 superfamily: amino acid sequence of a dimeric octahaem cytochrome c3 (Mr 26,000) isolated from Desulfovibrio gigas." Biochemical Journal 320, no. 3 (December 15, 1996): 933–38. http://dx.doi.org/10.1042/bj3200933.
Full textAbstract:
Cytochrome c3 (Mr 26000) isolated from Desulfovibrio gigas is a dimeric cytochrome consisting of two identical subunits of 109 amino acids, each of which contains four haem groups. On the basis of its amino acid sequence, this cytochrome clearly belongs to the cytochrome c3 superfamily, and will be classified in class III of the c-type cytochromes as defined by Ambler [(1980) in From Cyclotrons to Cytochromes (Robinson, A. B. and Kaplan, N. O., eds.), pp. 263–279, Academic Press, London]. It contains ten cysteine and nine histidine residues in each subunit, and eight cysteines and eight histidines linked to the four haem groups were found to be invariant on alignment of all known cytochrome c3 sequences. Two intermolecular disulphide bridges have been determined between cysteine residues 5 and 46 of the two monomers. Cytochrome c3 (Mr 26000) from D. gigas is clearly different from cytochrome c3 (Mr 13000) from the same strain, with which it shows only 27% sequence identity. Compared with cytochrome c3 (Mr 26000) from D. desulfuricans Norway, the three-dimensional structure of which has been determined, 26.95% of the residues have been conserved. In the enzyme from D. desulfuricans Norway, hydrophobic interactions have been described across the dimer interface. Residues involved in similar interactions seem to be well conserved in the equivalent D. gigas cytochrome. This sequence provides structural data to allow specification of this new subclass of polyhaem cytochromes. Furthermore, D. gigas cytochrome c3 (Mr 26000) is the first polyhaem cytochrome shown to contain two disulphide bridges linking two identical subunits, which could induce more rigid folding. The folding and the evolution of this family of polyhaem cytochromes are discussed.
28
Gao, Tao, and Mark R. O'Brian. "Control of DegP-Dependent Degradation of c-Type Cytochromes by Heme and the Cytochrome c Maturation System in Escherichia coli." Journal of Bacteriology 189, no. 17 (July 6, 2007): 6253–59. http://dx.doi.org/10.1128/jb.00656-07.
Full textAbstract:
ABSTRACT c-type cytochromes are located partially or completely in the periplasm of gram-negative bacteria, and the heme prosthetic group is covalently bound to the protein. The cytochrome c maturation (Ccm) multiprotein system is required for transport of heme to the periplasm and its covalent linkage to the peptide. Other cytochromes and hemoglobins contain a noncovalently bound heme and do not require accessory proteins for assembly. Here we show that Bradyrhizobium japonicum cytochrome c 550 polypeptide accumulation in Escherichia coli was heme dependent, with very low levels found in heme-deficient cells. However, apoproteins of the periplasmic E. coli cytochrome b 562 or the cytosolic Vitreoscilla hemoglobin (Vhb) accumulated independently of the heme status. Mutation of the heme-binding cysteines of cytochrome c 550 or the absence of Ccm also resulted in a low apoprotein level. These levels were restored in a degP mutant strain, showing that apocytochrome c 550 is degraded by the periplasmic protease DegP. Introduction of the cytochrome c heme-binding motif CXXCH into cytochrome b 562 (c-b 562) resulted in a c-type cytochrome covalently bound to heme in a Ccm-dependent manner. This variant polypeptide was stable in heme-deficient cells but was degraded by DegP in the absence of Ccm. Furthermore, a Vhb variant containing a periplasmic signal peptide and a CXXCH motif did not form a c-type cytochrome, but accumulation was Ccm dependent nonetheless. The data show that the cytochrome c heme-binding motif is an instability element and that stabilization by Ccm does not require ligation of the heme moiety to the protein.
29
Chateau, Alice, Béatrice Alpha-Bazin, Jean Armengaud, and Catherine Duport. "Heme A Synthase Deficiency Affects the Ability of Bacillus cereus to Adapt to a Nutrient-Limited Environment." International Journal of Molecular Sciences 23, no. 3 (January 18, 2022): 1033. http://dx.doi.org/10.3390/ijms23031033.
Full textAbstract:
The branched aerobic respiratory chain in Bacillus cereus comprises three terminal oxidases: cytochromes aa3, caa3, and bd. Cytochrome caa3 requires heme A for activity, which is produced from heme O by heme A synthase (CtaA). In this study, we deleted the ctaA gene in B. cereus AH187 strain, this deletion resulted in loss of cytochrome caa3 activity. Proteomics data indicated that B. cereus grown in glucose-containing medium compensates for the loss of cytochrome caa3 activity by remodeling its respiratory metabolism. This remodeling involves up-regulation of cytochrome aa3 and several proteins involved in redox stress response—to circumvent sub-optimal respiratory metabolism. CtaA deletion changed the surface-composition of B. cereus, affecting its motility, autoaggregation phenotype, and the kinetics of biofilm formation. Strikingly, proteome remodeling made the ctaA mutant more resistant to cold and exogenous oxidative stresses compared to its parent strain. Consequently, we hypothesized that ctaA inactivation could improve B. cereus fitness in a nutrient-limited environment.
30
Bergmann, David J., James A. Zahn, Alan B. Hooper, and Alan A. DiSpirito. "Cytochrome P460 Genes from the MethanotrophMethylococcus capsulatus Bath." Journal of Bacteriology 180, no. 24 (December 15, 1998): 6440–45. http://dx.doi.org/10.1128/jb.180.24.6440-6445.1998.
Full textAbstract:
ABSTRACT P460 cytochromes catalyze the oxidation of hydroxylamine to nitrite. They have been isolated from the ammonia-oxidizing bacteriumNitrosomonas europaea (R. H. Erickson and A. B. Hooper, Biochim. Biophys. Acta 275:231–244, 1972) and the methane-oxidizing bacterium Methylococcus capsulatus Bath (J. A. Zahn et al., J. Bacteriol. 176:5879–5887, 1994). A degenerate oligonucleotide probe was synthesized based on the N-terminal amino acid sequence of cytochrome P460 and used to identify a DNA fragment from M. capsulatus Bath that containscyp, the gene encoding cytochrome P460. cyp is part of a gene cluster that contains three open reading frames (ORFs), the first predicted to encode a 59,000-Da membrane-bound polypeptide, the second predicted to encode a 12,000-Da periplasmic protein, and the third (cyp) encoding cytochrome P460. The products of the first two ORFs have no apparent similarity to any proteins in the GenBank database. The overall sequence similarity of the P460 cytochromes from M. capsulatus Bath and N. europaea was low (24.3% of residues identical), although short regions of conserved residues are present in the two proteins. Both cytochromes have a C-terminal, c-heme binding motif (CXXCH) and a conserved lysine residue (K61) that may provide an additional covalent cross-link to the heme (D. M. Arciero and A. B. Hooper, FEBS Lett. 410:457–460, 1997). Gene probing usingcyp indicated that a cytochrome P460 similar to that fromM. capsulatus Bath may be present in the type II methanotrophs Methylosinus trichosporium OB3b andMethylocystis parvus OBBP but not in the type I methanotrophs Methylobacter marinus A45,Methylomicrobium albus BG8, and Methylomonassp. strains MN and MM2. Immunoblot analysis with antibodies against cytochrome P460 from M. capsulatus Bath indicated that the expression level of cytochrome P460 was not affected either by expression of the two different methane monooxygenases or by addition of ammonia to the culture medium.
31
Feissner, Robert E., Caroline S. Beckett, Jennifer A. Loughman, and Robert G. Kranz. "Mutations in Cytochrome Assembly and Periplasmic Redox Pathways in Bordetella pertussis." Journal of Bacteriology 187, no. 12 (June 15, 2005): 3941–49. http://dx.doi.org/10.1128/jb.187.12.3941-3949.2005.
Full textAbstract:
ABSTRACT Transposon mutagenesis of Bordetella pertussis was used to discover mutations in the cytochrome c biogenesis pathway called system II. Using a tetramethyl-p-phenylenediamine cytochrome c oxidase screen, 27 oxidase-negative mutants were isolated and characterized. Nine mutants were still able to synthesize c-type cytochromes and possessed insertions in the genes for cytochrome c oxidase subunits (ctaC, -D, and -E), heme a biosynthesis (ctaB), assembly of cytochrome c oxidase (sco2), or ferrochelatase (hemZ). Eighteen mutants were unable to synthesize all c-type cytochromes. Seven of these had transposons in dipZ (dsbD), encoding the transmembrane thioreduction protein, and all seven mutants were corrected for cytochrome c assembly by exogenous dithiothreitol, which was consistent with the cytochrome c cysteinyl residues of the CXXCH motif requiring periplasmic reduction. The remaining 11 insertions were located in the ccsBA operon, suggesting that with the appropriate thiol-reducing environment, the CcsB and CcsA proteins comprise the entire system II biosynthetic pathway. Antiserum to CcsB was used to show that CcsB is absent in ccsA mutants, providing evidence for a stable CcsA-CcsB complex. No mutations were found in the genes necessary for disulfide bond formation (dsbA or dsbB). To examine whether the periplasmic disulfide bond pathway is required for cytochrome c biogenesis in B. pertussis, a targeted knockout was made in dsbB. The DsbB− mutant makes holocytochromes c like the wild type does and secretes and assembles the active periplasmic alkaline phosphatase. A dipZ mutant is not corrected by a dsbB mutation. Alternative mechanisms to oxidize disulfides in B. pertussis are analyzed and discussed.
32
Kim, Jae-Hwan, Mi-Jeong Byun, Yeoung-Gyu Ko, Sung-Woo Kim, Sang-Woo Kim, Yoon-Jung Do, Myung-Jick Kim, Sei-Hyung Yoon, and Seong-Bok Choi. "Phylogenetic Analysis of Korean Native Goats Based on the Mitochondrial Cytochrome b Gene." Journal of Animal Science and Technology 54, no. 4 (August 31, 2012): 241–46. http://dx.doi.org/10.5187/jast.2012.54.4.241.
Full text
33
Koroleva, P. I., and V. V. Shumyantseva. "Design of model systems based on cytochrome P450 3A4 and riboflavin complexes for increasing the electrocatalysis efficiency." Journal Biomed 17, no. 3E (October 26, 2021): 37–41. http://dx.doi.org/10.33647/2713-0428-17-3e-37-41.
Full textAbstract:
Cytochromes P450 (CYP) are a large class of enzymes, whose active site is type b heme. The main function of cytochromes P450 is biotransformation of endogenous and exogenous compounds in the organism. The cytochrome P450 3A4 metabolizes about 50% of all modern medications; therefore, its catalytic properties present significant research interest. P450 cytochromes can be effectively investigated using electrochemical systems that consist of a solid base (electrode) and a modifier facilitating enzyme immobilization. In this case, the electron donor is an electrode substituting a natural electron donor NAD(P)H and eliminating the need to use redox-partner proteins. The electrode modifier maintains the catalytic enzyme activity and enhances the efficiency of electron transfer when noble metals and carbon materials nanoparticles are included. This work is aimed at creating more effective cytochrome P450 electrochemical systems to increase the yield of metabolites of enzymatic electrocatalytic reactions.
34
Hagmeyer, Lars. "E-Zigarette hat weitreichende biologische Auswirkungen auf das Bronchialepithel - Erkenntnisse aus proteomischen Analysen." Kompass Pneumologie 7, no. 4 (2019): 194–95. http://dx.doi.org/10.1159/000500656.
Full textAbstract:
Hintergrund: E-Zigaretten werden von den Herstellern häufig als Alternative zum inhalativen Tabakrauchkonsum propagiert. Sie verdampfen Propylenglykol/pflanzliches Glyzerin (PGlyk/pGlyz), Nikotin und Aromastoffe. Die gesundheitlichen Auswirkungen der verdampften E-Liquid-Substanzen auf die Lunge sind unklar. Fragestellung: In der Studie wurden in vitro und in vivo die chronischen Effekte verdampfter E-Liquid-Substanzen auf das Bronchialepithel untersucht. Material/Methoden: Bronchoskopisch wurden gesunde Nichtraucher, Zigarettenraucher und E-Zigaretten-Nutzer (Vaper; von engl. to vape = verdampfen) untersucht. Bronchoskopisch wurden Bürstenzytologien zur Durchführung proteomischer Analysen gewonnen. Außerdem wurden Analysen in vitro und im Mausmodell durchgeführt, um den Vaping-Effekt zu untersuchen. Ergebnisse: Bronchoskopisch fand sich die Bronchialschleimhaut der Vaper erythematös. Die Analysen aus den bronchoskopisch gewonnenen Epithelzellen detektierten bei Zigarettenrauchern und Vapern fast 300 Proteine, deren Expressionslevel im Vergleich zu den Nichtraucherprobanden verändert waren. Dabei waren nur 78 Proteine gleichermaßen in beiden Expositionsgruppen, jedoch 113 nur bei den Vapern verändert. Unter anderem waren die Level von CYP1B1 (Cytochrom P450 family 1 subfamily B member 1), MUC5AC (mucin 5 AC) und MUC4 bei den Vapern erhöht. Reines PGlyk/pGlyz-Aerosol führte zu einer signifikanten Erhöhung des MUC5AC-Proteins in humanen Atemwegsepithel-Kulturen und in murinen Nasenepithelzellen in vivo. Es konnte gezeigt werden, dass E-Liquids schnell nach intrazellulär penetrieren und dass PGlyk/pGlyz die zelluläre Membranfluidität reduziert und die Proteindiffusion beeinträchtigt. Schlussfolgerung: Der chronische Gebrauch von E-Zigaretten hat in der Lunge deutliche biologische Auswirkungen. Diese Auswirkungen sind möglicherweise zum Teil durch das PGlyk/pGlyz-Aerosol verursacht. Die beobachteten Veränderungen sind wahrscheinlich nicht als harmlos einzustufen und könnten durchaus von klinischer Bedeutung sein und die Entstehung chronischer Lungenerkrankungen begünstigen. Weitere Studien müssen die Folgen der E-Zigarette für die Lunge weiter herausarbeiten.
35
Piantadosi, C. A., A. L. Sylvia, H. A. Saltzman, and F. F. Jobsis-Vandervliet. "Carbon monoxide-cytochrome interactions in the brain of the fluorocarbon-perfused rat." Journal of Applied Physiology 58, no. 2 (February 1, 1985): 665–72. http://dx.doi.org/10.1152/jappl.1985.58.2.665.
Full textAbstract:
Reflectance spectrophotometry through the skull was used to investigate carbon monoxide (CO) binding by tissue hemoproteins in the brains of barbiturate-anesthetized Sprague-Dawley rats. After splenectomy and extensive perfluorotributylamine exchange transfusion, steady-state spectral scans were obtained in Soret and visible wave-length regions during O2 ventilation, during subsequent exposure to O2-enriched gases containing 1, 3, or 5% CO, and finally after N2 anoxia. These CO exposures were well-tolerated and electroencephalograph (EEG) activity continued to be present. Initial difference spectra were influenced by CO binding to residual hemoglobin, but spectral evidence of CO-mediated b-type cytochrome reduction was obtained in the visible region as CO concentration was increased to 3 or 5%. This was associated with Soret spectra compatible with formation of the reduced cytochrome a3-CO complex. Reduction of cytochrome a at 605 nm and cytochrome c + c1 at 550 nm was absent. These findings may indicate respiratory chain branching through b cytochromes, either to a separate a3-like oxidase independent of the classical cytochrome aa3 or to an unidentified alternative CO-sensitive oxidase.
36
de Vries, Wytske, Willemina M. C. van Wijck-Kapteyn, and S. K. H. Oosterhuis. "The Presence and Function of Cytochromes in Selenomonas ruminantium, Anaerovibrio lipolytica and Veillonella alcalescens." Microbiology 81, no. 1 (January 1, 2000): 69–78. http://dx.doi.org/10.1099/00221287-81-1-69.
Full textAbstract:
Strains of Selenomonas ruminantium, Anaerovibrio lipolytica and Veillonella alcalescens contained cytochrome b. Peaks corresponding to cytochromes a and a carbon monoxide-binding pigment were also observed. By means of dual-wavelength experiments with crude membrane fractions it was established that cytochrome b functioned in anaerobic electron transport to fumarate. In V. alcalescens and one strain of S. ruminantium which reduced nitrate, anaerobic electron transport to nitrate was found. Glycerol 1-phosphate and NADH were active as hydrogen donors for cytochrome b reduction in glycerol-grown A. lipolytica, lactate and pyruvate were active in lactate-grown V. alcalescens, and NADH was active in lactose-grown S. ruminantium. Oxidative phosphorylation associated with these electron transfer systems might explain the high molar growth yields previously found for these micro-organisms. Fermentation products were measured in supernatant fluids of cultures grown in the presence and absence of nitrate. Nitrate did not influence the fermentation of lactose to lactate by S. ruminantium, and inhibited propionate formation by V. alcalescens.
37
Ferguson, S. J. "Keilin's Cytochromes: How Bacteria Use Them, Vary Them and Make Them." Biochemical Society Transactions 29, no. 6 (November 1, 2001): 629–40. http://dx.doi.org/10.1042/bst0290629.
Full textAbstract:
Many proteins with one or more haem groups bound per polypeptide chain are called cytochromes. They function in electron transfer reactions and some are involved directly in the catalysis of chemical reactions, most prominently the reduction of oxygen to water in the terminal step of cell respiration. When unmodified haem is present the cytochromes are referred to as b-type, but if the haem is covalently attached to thiol groups of a Cys-Xaa-Xaa-Cys-His motif then the cytochrome is a c-type. Neither the purpose of this post-translational modification, nor the mechanisms of the machineries that are necessary for formation of the thioether bonds between protein and haem, are fully understood. In bacteria the c-type cytochromes function in the periplasm where they are involved in a range of electron transport activities, including the reactions of denitrification, in which nitrate is reduced sequentially via nitrite, nitric oxide and nitrous oxide to nitrogen gas. Other types of cytochromes have haem molecules with modifications to their porphyrin ring. These include the a-, d-, d1- and o-types. Although Keilin first described the a-, b- and c- types of cytochrome more than 60 years ago, we still do not have clear explanations as to why one type of haem moiety does not suffice for the requirements of mitochondrial, thylakoid and bacterial electron transport.
38
Winstedt, Lena, and Claes von Wachenfeldt. "Terminal Oxidases of Bacillus subtilisStrain 168: One Quinol Oxidase, Cytochromeaa3 or Cytochrome bd, Is Required for Aerobic Growth." Journal of Bacteriology 182, no. 23 (December 1, 2000): 6557–64. http://dx.doi.org/10.1128/jb.182.23.6557-6564.2000.
Full textAbstract:
ABSTRACT The gram-positive endospore-forming bacterium Bacillus subtilis has, under aerobic conditions, a branched respiratory system comprising one quinol oxidase branch and one cytochrome oxidase branch. The system terminates in one of four alternative terminal oxidases. Cytochrome caa 3 is a cytochromec oxidase, whereas cytochrome bd and cytochromeaa 3 are quinol oxidases. A fourth terminal oxidase, YthAB, is a putative quinol oxidase predicted from DNA sequence analysis. None of the terminal oxidases are, by themselves, essential for growth. However, one quinol oxidase (cytochromeaa 3 or cytochrome bd) is required for aerobic growth of B. subtilis strain 168. Data indicating that cytochrome aa 3 is the major oxidase used by exponentially growing cells in minimal and rich medium are presented. We show that one of the two heme-copper oxidases, cytochrome caa 3 or cytochromeaa 3, is required for efficient sporulation ofB. subtilis strain 168 and that deletion of YthAB in a strain lacking cytochrome aa 3 makes the strain sporulation deficient.
39
Yusman Maulid, Deden, Mala Nurilmala, Nurjanah Nurjanah, and Hawis Maduppa. "Molecular Characteristics of Cytochrome B for Mackerel Barcoding." Jurnal Pengolahan Hasil Perikanan Indonesia 19, no. 1 (April 26, 2016): 9–16. http://dx.doi.org/10.17844/jphpi.2016.19.1.9.
Full text
40
Kim, Jae-Hwan, ChangYeon Cho, SeungChang Kim, Sung Woo Kim, Seong-Bok Choi, and Seong-Su Lee. "Phylogenetic Characterization of White Hanwoo Using the Mitochondrial Cytochrome b Gene." Journal of Life Science 25, no. 9 (September 30, 2015): 970–75. http://dx.doi.org/10.5352/jls.2015.25.9.970.
Full text
41
Piantadosi, C. A., P. A. Lee, and A. L. Sylvia. "Direct effects of CO on cerebral energy metabolism in bloodless rats." Journal of Applied Physiology 65, no. 2 (August 1, 1988): 878–87. http://dx.doi.org/10.1152/jappl.1988.65.2.878.
Full textAbstract:
Cerebrocortical b-cytochromes have been found to be sensitive to reduction in the presence of CO and O2 in vivo. CO-mediated cytochrome b reduction responses in "bloodless" rats were correlated in this study with changes in concentrations of high energy and glycolytic intermediates measured in cortex after rapid brain freezing. Cytochrome redox state and metabolite concentrations also were compared with cerebral blood flow (CBF) and cerebral metabolic rate for O2 (CMRo2) measured before and after CO administration. No definite biochemical evidence of energy limitation was found in parietal cortex after the fluorocarbon-for-blood exchange; however, CO had direct effects on brain metabolite concentrations. Fifteen-minute CO exposures at inspired CO/O2 of 0.003-0.06 increased cerebrocortical phosphocreatine and ADP and decreased creatine concentration. CO exposure produced no significant changes in either ATP concentration or CMRo2, although CBF increased slightly. These findings may be interpreted to indicate that CO binding to cytochrome aa3 at low CO/O2 in vivo increases extramitochondrial pH relative to that within the mitochondrial matrix. In the process, cytochrome b reduction levels increase, possibly signaling an increased efficiency of oxidative phosphorylation relative to O2 uptake by unblocked respiratory chains.
42
Sylvia, Avis L., and Claude A. Piantadosi. "O2 Dependence of in vivo Brain Cytochrome Redox Responses and Energy Metabolism in Bloodless Rats." Journal of Cerebral Blood Flow & Metabolism 8, no. 2 (April 1988): 163–72. http://dx.doi.org/10.1038/jcbfm.1988.45.
Full textAbstract:
Oxygen-dependent changes in brain cytochrome redox state and cerebrocortical energy metabolism were evaluated in fluorocarbon-circulated rats at hematocrits of <1%. Redox levels of three respiratory chain cytochrome complexes, b, c, and a,a3 (cytochrome c oxidase), were continuously measured directly through the intact skulls of animals using reflectance spectrophotometry. The in vivo redox status of cytochromes at different Fio2 was directly compared with in vitro measured changes in cortical metabolites known to reflect energy production, i.e., glucose, pyruvate, lactate, phosphocreatine (PCr), ADP, and ATP. Lowering the Fio2 to <1.0 caused the cytochromes to become increasingly more reduced. This was associated with increased tissue accumulation of pyruvate and lactate and a concomitant increase in the lactate/pyruvate (L/P) ratio. At Fio2 = 0.6, cytochromes b, c, and a,a3 were 57, 53, and 46% reduced, respectively. There was no apparent cerebral energy deficit since changes in cortical PCr, ADP, and ATP concentrations were not statistically significant. Bloodless animals did not survive below Fio2 = 0.5. At this Fio2, the inability of the animals to sustain arterial pressure correlated ( r = 0.87) with depletion of PCr and further increases in the L/P ratio ( r = 0.66). Yet, the cortical ATP content was reduced by only 9% of control value. These data provide direct evidence that fluorocarbon emulsion (FC-43) sustains brain oxygenation and energy metabolism at high partial pressures of molecular o2. At lower Fio2, however, mitochondrial o2 uptake becomes limited as a function of decreasing perfusion pressure.
43
MAGNUSON, Timothy S., Naohito ISOYAMA, Allison L. HODGES-MYERSON, Gerard DAVIDSON, Michael J. MARONEY, Gill G. GEESEY, and Derek R. LOVLEY. "Isolation, characterization and gene sequence analysis of a membrane-associated 89 kDa Fe(III) reducing cytochrome c from Geobacter sulfurreducens." Biochemical Journal 359, no. 1 (September 24, 2001): 147–52. http://dx.doi.org/10.1042/bj3590147.
Full textAbstract:
Geobacter sulfurreducens is capable of anaerobic respiration with Fe(III) as a terminal electron acceptor via a membrane-bound Fe(III) reductase activity associated with a large molecular mass cytochrome c. This cytochrome was purified by detergent extraction of the membrane fraction, Q-Sepharose ion-exchange chromatography, preparative electrophoresis, and MonoQ ion-exchange chromatography. Spectrophotometric analysis of the purified cytochrome reveals a c-type haem, with no evidence of haem a, haem b or sirohaem. The cytochrome has an Mr of 89000 as determined by denaturing PAGE, and has an isoelectric point of 5.2 as determined by analytical isoelectric focusing. Dithionite-reduced cytochrome can donate electrons to Fe(III)-nitrilotriacetic acid and synthetic ferrihydrite, thus demonstrating that the cytochrome has redox and thermodynamic properties required for reduction of Fe(III). Analysis using cyclic voltammetry confirmed that the reduced cytochrome can catalytically transfer electrons to ferrihydrite, further demonstrating its ability to be an electron transport mediator in anaerobic Fe(III) respiration. Sequence analysis of a cloned chromosomal DNA fragment revealed a 2307bp open reading frame (ferA) encoding a 768 amino acid protein corresponding to the 89kDa cytochrome. The deduced amino acid sequence (FerA) translated from the open reading frame contained 12 putative haem-binding motifs, as well as a hydrophobic N-terminal membrane anchor sequence, a lipid-attachment site and an ATP/GTP-binding site. FerA displayed 20% or less identity with amino acid sequences of other known cytochromes, although it does share some features with characterized polyhaem cytochromes c.
44
Abendroth, Annalena, Carsta Seifert, Derik Hermsen, Stefanie Ackerstaff, and Till Hoffmann. "Ginkgo, Ginseng und Gerinnung." Zeitschrift für Phytotherapie 42, no. 06 (November 25, 2021): 301–11. http://dx.doi.org/10.1055/a-1540-9850.
Full textAbstract:
ZusammenfassungDie Anwendung von Phytotherapeutika aufgrund unterschiedlichster Indikationen ist auch bei Patienten mit kardiovaskulären Erkrankungen weit verbreitet. Dabei stellt der gleichzeitige Einsatz von Antikoagulanzien ein oft unterschätztes pharmakologisches Sicherheitsrisiko dar. Durch die Zunahme der präferenziellen Verordnung direkter oraler Antikoagulanzien (DOAK) zur Therapie und Prophylaxe thromboembolischer Ereignisse sowie die stetige Zulassungserweiterung der DOAK in der letzten Dekade, ist die Einschätzung möglicher Arzneimittelinteraktionen und gerinnungsmodifizierender Wirkungen bei gleichzeitiger Anwendung von Phytotherapeutika eine besondere Herausforderung. Dabei sind einerseits direkte gerinnungs- oder thrombozytenhemmende Effekte einiger Pflanzenwirkstoffe selbst zu bedenken, welche zu einem erhöhten Blutungsrisiko führen können. Andererseits kann es zu komplexen Wechselwirkungen im Sinne metabolischer Arzneimittelinteraktionen zwischen Phytotherapeutika und gerinnungshemmenden Pharmaka kommen. Zwar erscheint das Interaktionspotenzial der DOAK im Vergleich zu den Vitamin-K-Antagonisten (VKA) als insgesamt deutlich geringer, jedoch können pharmakokinetische Interaktionen über das Cytochrom-P450- und P-Glykoprotein-System sowohl zu Konzentrationserhöhungen mit nachfolgendem Blutungsrisiko als auch zu einer Wirkspiegelreduktion mit nachfolgend unzureichendem antikoagulatorischem Effekt der DOAK führen. Darüber hinaus sind für viele populäre Phytotherapeutika wie etwa Ginkgo, Ginseng, Knoblauch oder Ingwer nachweisbare inhibitorische Wirkungen auf die Thrombozytenfunktion bekannt. Diese können durch additive Arzneimittelwirkungen in der Kombination mit DOAK zu ernstzunehmenden Blutungsneigungen führen. Im klinischen Alltag ist die Einschätzung relevanter Blutungsrisiken durch phyto-pharmakotherapeutische Kombinationstherapien oft aufwändig und schwierig, da bisher vorwiegend Fallberichte und nur wenige studienbasierte Daten zu möglichen Interaktionen mit DOAK vorliegen. Eine Hilfestellung bieten hier verschiedene pharmakologische Datenbanken. Um mögliche Auswirkungen auf die Thrombozytenfunktion zu erfassen, stehen hämostaseologische Spezialuntersuchungen, wie z. B. die Lichttransmissionsaggregometrie (LTA) zur Verfügung. Dennoch bedarf es weiterer klinischer Studien und Fallsammlungen, um die Arzneimittelsicherheit in der Kombinationsbehandlung mit DOAK und Phytotherapeutika für Patient*innen und Ärzt*innen zu verbessern. Dieser Artikel soll einen Überblick über den aktuellen Kenntnisstand und relevante Wechselwirkungen populärer Phytotherapeutika geben.
45
Jaramillo, Rubén D., Beatriz C. Barraza, Alma Polo, Martín Sará, Martha Contreras, and J. Edgardo Escamilla. "The aerobic electron transport system ofEikenella corrodens." Canadian Journal of Microbiology 48, no. 10 (October 1, 2002): 895–902. http://dx.doi.org/10.1139/w02-084.
Full textAbstract:
The respiratory system of the fastidious β-proteobacterium Eikenella corrodens grown with limited oxygen was studied. Membranes showed the highest oxidase activity with ascorbate plus N,N,N',N'-tetramethyl-p-phenyl enediamine (TMPD) or succinate and the lowest activity with NADH and formate. The presence of a bc1-type complex was suggested by the inhibition exerted by 2-heptyl-4-hydroxyquinoline-N-oxide (HOQNO), myxothiazol, and antimycin A on respiration with succinate and by the effect of the latter two inhibitors on the succinate-reduced difference spectra. Respiration with succinate or ascorbateTMPD was abolished by low KCN concentrations, suggesting the presence of a KCN-sensitive terminal oxidase. Cytochromes b and c were spectroscopically detected after reduction with physiological or artificial electron donors, whereas type a and d cytochromes were not detected. The CO difference spectrum of membranes reduced by dithionite and its photodissociation spectrum (77 K) suggested the presence of a single CO compound that had the spectral features of a cytochrome o-like pigment. High-pressure liquid chromatography analysis of membrane haems confirmed the presence of haem B; in contrast, haems A and O were not detected. Peroxidase staining of membrane type c cytochromes using SDSPAGE revealed the presence of five bands with apparent molecular masses of 44, 33, 30, 26, and 14 kDa. Based on our results, a tentative scheme of the respiratory chain in E. corrodens, comprising (i) dehydrogenases for succinate, NADH, and formate, (ii) a ubiquinone, (iii) a cytochrome bc1, and (iv) a type-cbb' cytochrome c oxidase, is proposed. Key words: Eikenella corrodens, respiratory chain, bc1complex, oxidase cbb'.
46
Nikolaeva, V. M., V. V. Fokina, A. A. Shutov, A. V. Kazantsev, N. I. Strizhov, and M. V. Donova. "Construction and Functional Analysis of Mycolicibacterium smegmatis Recombinant Strains Carrying the Genes of Bacillary Cytochromes CYP106A1 and CYP106A2." Biotekhnologiya 37, no. 6 (2021): 34–47. http://dx.doi.org/10.21519/0234-2758-2021-37-6-34-47.
Full textAbstract:
Mycolicibacterium smegmatis mc2155 has been genetically modified to be used as a platform for the expression of foreign cytochrome P450 monooxygenases by introducing deletions in the kshB and kstD genes that encode key stages of the enzymatic destruction of the steroid nucleus. Three sets of genetic constructs have been created for heterologous expression of the genes of cytochromes P450 CYP106A1 from Bacillus megaterium DSM319 and CYP106A2 from Bacillus megaterium ATCC13368 in Mycolicibacterium smegmatis mc2155 (ΔkshBΔkstD) cells. The recombinant plasmids contained monocistronic expression cassettes of cytochrome genes (NS31 and pNS32), or tricistronic cassettes of cytochrome genes together with cDNA copies of adrenodoxin and andrenodoxin reductase genes of the bovine adrenal cortex (pNS33 and pNS34), or monocistronic gene cassettes of chimeric cytochromes fused with the DNA sequence encoding the CYP116B2 reductase domain from the soil bacterium Rhodococcus sp. NCIMB 9784 (pNS35 and pNS36). The recombinant strains of mycolicibacteria were shown to selectively monohydroxylate androstenedione (AD) under growth conditions. The product was identified as 15-hydroxyandrostenedione (15-OH-AD) by mass spectrometry and 1H and 13C NMR spectroscopy. The maximum level of 15-OH-AD production (17.3 ± 1.5 mg/L) was observed when using the recombinant M. smegmatis mc2155 (ΔkshBΔkstD) (pNS32) strain, which expresses a single cyp106A2 gene from B. megaterium ATCC13368. Host proteins of M. smegmatis mc2155 were shown to be capable of supplying electrons to heterologous cytochromes to support their hydroxylating activity. The results are of priority character, expand the understanding of the hydroxylation of steroid compounds by bacterial cytochromes CYP106A1/A2 and are important for the creation of microbial strains producing valuable hydroxysteroids. cyp106A1, cyp106A2, cytochrome P450, heterologous expression, Bacillus megaterium, Mycolicibacterium smegmatis, 15β-hydroxylation, bioconversion, steroids This work was supported by the Russian Science Foundation (project No. 21-64-00024).
47
Sesardic, D., A. R. Boobis, J. McQuade, S. Baker, E. A. Lock, C. R. Elcombe, R. T. Robson, C. Hayward, and D. S. Davies. "Inter-relatedness of some isoenzymes of cytochrome P-450 from rat, rabbit and human, determined with monoclonal antibodies." Biochemical Journal 236, no. 2 (June 1, 1986): 569–77. http://dx.doi.org/10.1042/bj2360569.
Full textAbstract:
Monoclonal antibodies have been raised to rat liver cytochromes P-450 b and c, and rabbit liver cytochrome P-450 form 4. A total of six antibodies have been studied. Each antibody reacted strongly both with its homologous antigen and with microsomal fractions selectively enriched with that antigen by treatment of animals with inducing compounds. However, several of the antibodies showed cross-reactivity, either within or between species. A combination of enzyme-linked immunosorbent assay, immunoadsorption, Western blotting and competitive radioimmunoassay revealed that each of the antibodies reacted with a different epitope. Proteolytic digestion of antigen followed by Western blotting of the peptide fragments enabled antibodies, otherwise identical in their reactivity, to be distinguished. It is concluded that complex structural relationships exist amongst the different isoenzymes of cytochrome P-450 and that epitope mapping will help in characterizing both animal and human cytochromes P-450.
48
Hodson, Christopher T. C., Allison Lewin, Lars Hederstedt, and Nick E. Le Brun. "The Active-Site Cysteinyls and Hydrophobic Cavity Residues of ResA Are Important for Cytochrome c Maturation in Bacillus subtilis." Journal of Bacteriology 190, no. 13 (May 2, 2008): 4697–705. http://dx.doi.org/10.1128/jb.00145-08.
Full textAbstract:
ABSTRACT ResA is an extracytoplasmic membrane-bound thiol-disulfide oxidoreductase required for cytochrome c maturation in Bacillus subtilis. Previous biochemical and structural studies have revealed that the active-site cysteinyls cycle between oxidized and reduced states with a low reduction potential and that, upon reduction, a hydrophobic cavity forms close to the active site. Here we report in vivo studies of ResA-deficient B. subtilis complemented with a series of ResA variants. Using a range of methods to analyze the cellular cytochrome c content, we demonstrated (i) that the N-terminal transmembrane segment of ResA serves principally to anchor the protein to the cytoplasmic membrane but also plays a role in mediating the activity of the protein; (ii) that the active-site cysteines are important for cytochrome c maturation activity; (iii) that Pro141, which forms part of the hydrophobic cavity and which adopts a cis conformation, plays an important role in protein stability; (iv) that Glu80, which lies at the base of the hydrophobic cavity, is important for cytochrome c maturation activity; and, finally, (v) that Pro141 and Glu80 ResA mutant variants promote selective maturation of low levels of one c-type cytochrome, subunit II of the cytochrome c oxidase caa 3, indicating that this apocytochrome is distinct from the other three endogenous c-type cytochromes of B. subtilis.
49
Smith, M. A., A. R. Cross, O. T. G. Jones, W. T. Griffiths, S. Stymne, and K. Stobart. "Electron-transport components of the 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine Δ12-desaturase (Δ12-desaturase) in microsomal preparations from developing safflower (Carthamus tinctorius L.) cotyledons." Biochemical Journal 272, no. 1 (November 15, 1990): 23–29. http://dx.doi.org/10.1042/bj2720023.
Full textAbstract:
The major cytochrome in microsomal membrane preparations from developing seeds of safflower (Carthamus tinctorius, var High Linoleate), has a reduced-minus-oxidized difference spectrum characteristic of a b-type cytochrome, and was identified from its midpoint-potential (E'7.2) value as cytochrome b5. Cytochromes P-450 and P-420 were also present. The cytochrome b5 content of microsomal preparations from a number of oilseed species was found to be in the order of 200-300 pmol/mg of protein. The cytochrome b5 was reduced in the membrane preparations by NADH, demonstrating the presence of an NADH: cytochrome b5 reductase; NADPH was a less effective donor. Microsomal membranes catalysed the NAD(P)H-dependent conversion of radioactive oleate into linoleate, indicating acyl-CoA: lysophosphatidylcholine acyltransferase and 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine delta 12-desaturase (delta 12-desaturase) activity. Desaturation of oleate to linoleate was unaffected by CO, but inhibited by CN-. The addition of oleoyl-CoA to the NADH-reduced membranes resulted in the CN(-)-sensitive partial re-oxidation of cytochrome b5, indicating that electrons from NADH were transferred to the site of desaturation via this cytochrome. The delta 12-desaturase in safflower, therefore, is CN(-)-sensitive and appears to require cytochrome b5 and NADH: cytochrome b5 reductase for activity.
50
Kopylchuk, G. P., Z. M. I. Grynenkiv, and O. M. Voloshchuk. "CYTOCHROMES OF MITOCHONDRIES AND ACTIVITY OF HEME METABOLISM ENZYMES IN THE LIVER UNDER DIFFERENT NUTRIENT REGIMES." Fiziolohichnyĭ zhurnal 67, no. 2 (April 5, 2021): 37–43. http://dx.doi.org/10.15407/fz67.02.037.
Full textAbstract:
The content of mitochondrial cytochromes and the activity of key enzymes of heme metabolism in the liver of rats under conditions of different dietary supply of protein and sucrose were investigated. The quantitative determination of mitochondrial cytochrome was performed by differential spectrophotometry, δ-aminolevulinate synthase activity was determined spectrophotometrically taking into account the molar extinction coefficient of 0.023x10(3) M(-1)sm(-1). Hemoxygenase activity was determined using the amount of formed bilirubin. It was found that under conditions of consumption of high-sucrose diet a significant decrease in the content of all mitochondrial cytochromes is noted: the content of cytochromes aa3, b and c1 decreases within 1.2-1.7 times, and content of cytochrome c decreases in two times. In the case of excessive consumption of sucrose on the background of alimentary protein deprivation the content of cytochromes b and c1 in the liver of rats does not differ statistically from similar indicators of the group of animals kept on a high-sucrose diet. At the same time, the content of cytochromes aa3 and c is significantly reduced. According to the activity of δ-aminolevulinate synthase under conditions of consumption of a high-sucrose diet, the studied enzymatic activity decreases by about 1.5 times with a simultaneous increase in the activity of heme oxygenase. Thus, there is a marked decrease in heme synthesis against the background of increased catabolism, which explains the decrease in the content of cytochromes in the mitochondria of the liver of rats under conditions of excess sucrose in the diet. The maximum increase in the activity of heme oxygenase (almost threefold) is observed in animals that were kept on a high-sugar diet deficient in protein content. Thus, dietary protein deficiency is a critical factor affecting the heme metabolism in the mitochondria of liver cells. The established changes in the content of mitochondrial cytochromes and the activities of key enzymes of heme metabolism in the liver could be considered as prerequisites for deepening its energy imbalance in conditions of different supply of sucrose and protein in diet.