共查询到20条相似文献,搜索用时 31 毫秒
1.
Y Orii H Shimada T Nozawa M Hatano 《Biochemical and biophysical research communications》1977,76(4):983-988
A possibility of a heme-heme interaction between the heme and heme moieties in nitrite reductase was examined by using magnetic and natural circular dichroism. The MCD of the heme moiety in the ferric enzyme was similar to that of mammalian ferricytochrome in shape and intensity, whereas in the reduced state the MCD intensity was considerably smaller than that of ferrocytochrome . When the heme moiety was perturbed by the complex formation with CO, imidazole or cyanide as well as by pH changes, the depressed MCD was restored to the MCD level of mammalian ferrocytochrome , accompanying conformational changes around the prosthetic groups. Thus, it was concluded that the heme-heme interaction exists only in the reduced enzyme and that this interaction is released under appropriate conditions. 相似文献
2.
Jörg Eder Minoru Osanai Suresh Mane Heinz Rembold 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,496(2):401-411
The development of a sensitive viroimmunoassay for honey bee cytochrome and its usage for early detection of caste differentiation is described. Pure honey bee cytochrome was isolated from workers and used to produce antibodies in rabbits. Bacteriophage T4 was chemically modified by covalent attachment of honey bee cytochrome using tolylene-2,4-diisocyanate as a cross-linking agent. The immunospecific inactivation of this bacteriophage-cytochrome c conjugate by anti-cytochrome antibodies can be inhibited by free cytochrome . In quantitative determinations, 50% inhibition is reproducibly achieved at a concentration of 6 ng/ml (5 pmol/ml) and as little as 0.3 ng/ml (0.25 pmol/ml) could be detected by this system. Cytochrome concentrations were measured in individual animals and substantial differences between corresponding larval stages of worker and queen bees are reported. 相似文献
3.
Thermotropic properties of purified cytochrome and cytochrome have been studied by differential scanning calorimetry under various conditions. Both cytochromes exhibit a single endothermodenaturation peak in the differential scanning calorimetric thermogram. Thermodenaturation temperatures are ionic strength, pH, and redox state dependent. The ferrocytochromes are more stable toward thermodenaturation than the ferricytochromes. The enthalpy changes of thermodenaturation of ferro- and ferricytochrome are markedly dependent on the ionic strength of the solution. The effect of the ionic strength of solution on the enthalpy change of thermodenaturation of cytochrome is rather insignificant. The formation of a complex between cytochromes and at lower ionic strength causes a significant destabilization of the former and a slight stabilization of the latter. The destabilization of cytochrome upon mixing with cytochrome was also observed at high ionic strength, under which conditions no stable complex was detected by physical separation. This suggests formation of a transient complex between these two cytochromes. When cytochrome was complexed with phospholipids, no change in the thermodenaturation temperature was observed, but a great increase in the enthalpy change of thermodenaturation resulted. 相似文献
4.
A Novel function of cytochrome C (555, Chlorobium thiosulfatophilum) in oxidation of thiosulfate 总被引:2,自引:0,他引:2
Thiosulfate-cytochrome c-551 reductase derived from has been highly purified. The enzyme reduces cytochrome in the presence of thiosulfate while cytochrome -555 of the organism is not reduced by the enzyme. Cytochrome -555 reacts with the enzyme at an appreciable rate only in the presence of cytochrome -551. However, the reduction rate of cytochrome -551 by the enzyme is greatly enhanced on addition of a catalytic amount of cytochrome -555. Therefore, cytochrome -555 seems to function as an effector on thiosulfate-cytochrome -551 reductase as well as it acts as the electron donor to the light-excited chlorobium chlorophylls. 相似文献
5.
H.R. Bosshard M. Zürrer H. Schägger G. von Jagow 《Biochemical and biophysical research communications》1979,89(1):250-258
Cytochrome 1, the electron donor for cytochrome , is a subunit of the mitochondrial cytochrome 1 complex (complex III, cytochrome reductase). To test if cytochrome 1 is the cytochrome -binding subunit of the 1 complex, binding of cytochrome to the complex and to isolated cytochrome 1 was compared by a gel-filtration method under non-equilibrium conditions (a 1 complex lacking the Rieske ironsulfur protein was used; von Jagow et al. (1977) Biochim. Biophys. Acta , 549–558). The approximate stoichiometries and binding affinities were found to be very similar. Binding of cytochrome to isolated cytochrome which is another subunit of the reductase was not detectable by the gel-filtration method. Further, the same lysine residues of cytochrome were shielded towards chemical acetylation in the complexes 1 and 1. From this we conclude that the same surface area of cytochrome is in direct contact with cytochrome 1 and with cytochrome 1 in the respective complexes and that therefore cytochrome is most probably the structural ligand for cytochrome in mitochondrial cytochrome reductase. 相似文献
6.
J C Chien L C Dickinson T L Mason 《Biochemical and biophysical research communications》1975,63(4):853-857
An improved synthesis for cobalt-cytochrome has been developed; its half reduction potential is ?140 ± 20mV. Reduced Cocyt-3 is oxidized by bovine heart cytochrome oxidase at a rate ~45% that of the native cytochrome . It is not reduced by mitochondrial NADH or succinate cytochrome reductase nor by microsomal NADH or NADPH cytochrome reductase. 相似文献
7.
Y P Myer K K Thallum J Pande B C Verma 《Biochemical and biophysical research communications》1980,94(4):1106-1112
The ascorbate-TMPD-cytochrome oxidase and succinate cytochrome reductase activities and the redox potentials of native and chemically modified cytochromes with modification of Trp-59 and Met-65, nitro-cytochrome with modification of Tyr-67, and a new preparation, Chloramine-T-cytochrome m with modification of Met-80 and -65 to methionine sulfoxide—have been compared at pH 7.8 in 25 mM cacodylate-Tris buffer. These modifications exhibit (i) a slight lowering of redox potential, from 260 mV to 180, 215 and 170 mV, respectively, (ii) destabilization of the cytochrome -reductase complex, 6 to 12 fold, but without alteration of the cytochrome -oxidase complex, and (iii) a slight lowering of the maximum velocity for both the oxidase and reductase reactions. The selective destabilization of the cytochrome -reductase complex is interpreted as an indication of a two-path, two-function model for the oxido-reduction function of cytochrome . 相似文献
8.
The addition of formate to oxidized cytochrome oxidase (ferrocytochrome : oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high spin heme signal at g = 6 and a splitting of g = 3 signal to g = 2.98 and 3.07. When formate-cytochrome oxidase is reduced, the g = 2.98 signal decreases significantly. The spectrophotometric studies showed that formate is a specific ligand to cytochrome 3. Data suggest that binding of formate to oxidized cytochrome oxidase produces a ligand-3 interaction leading to the splitting of g = 3 signal hitherto considered as due to cytochrome . Thus both cytochrome and 3 contribute to the resonance of g = 3 signal of cytochrome oxidase. 相似文献
9.
Charge distribution in electron transport components: cytochrome c and cytochrome c oxidase mixtures
Mixtures of cytochrome oxidase and cytochrome have been titrated by coulometrically generated reductant, methyl viologen radical cation, and physiological oxidant, O2. Charge distribution among the heme components in mixtures of these two redox enzymes has been evaluated by monitoring the absorbance changes at 605 and 550 nm. Differences in the pathway of the electron transfer process during a reduction cycle as compared to an oxidation cycle are indicated by variations found in the absorbance behavior of the heme components during successive reductive and oxidative titrations. It is apparent that the potential of the cytochrome heme is dependent upon whether oxidation or reduction is occurring. 相似文献
10.
Susan E. Lewis 《Developmental biology》1978,65(2):553-557
This report describes the phenotype of the c25H lethal homozygote. Our studies have shown that embryos homozygous for c25H fail to implant and to induce a decidual reaction. Embryos arrested at the three- to six-cell stage were considered to be c25H homozygotes because of their homogeneous stage of arrest and because they were present in the appropriate proportion in preimplantation litters from matings. Mitosis appeared to be disturbed in the arrested embryos. 相似文献
11.
When ferrocytochrome reacts with delipidated cytochrome oxidase under conditions which prevent oxidation, one proton is taken up per molecule of ferrocytochrome bound to cytochrome oxidase. When ferricytochrome reacts with delipidated Complex III, one proton is released per molecule of ferricytochrome bound to Complex III. From these data it can be concluded that the oxidation of ferrocytochrome by cytochrome oxidase leads to the release of a proton and an electron, whereas the reduction of ferricytochrome by Complex III leads to the uptake of a proton and an electron. Thus ferrocytochrome like QH2 and NADH is both an electron and proton donor, and ferricytochrome like Q and O2 is both an electron and proton acceptor. The pattern for the three mitochondrial electron transfer sequences NADH → Q, QH2 → ferricytochrome and ferrocytochrome → O2 involves separation of an electron and proton on the side of the membrane where electron transfer is initiated and recombination of an electron and a proton in the terminal acceptor on the side of the membrane where electron transfer terminates. 相似文献
12.
J M Vanderkooi 《Biochemical and biophysical research communications》1976,69(4):1043-1049
Ferricytochrome can be reduced in a photochemical reaction by excited state phenothiazine. This reaction is observed between phenothiazine which is solubilized by phospholipid artificial membranes and cytochrome which is adsorbed to the membrane surface. Under conditions when cytochrome is not bound to the phospholipid, the rate of reduction by phenothiazine is greatly reduced. The phosphorescence of phenothiazine is quenched in the presence of cytochrome , implying that the excited triplet state interacts with cytochrome . Oxygen inhibits the reaction since possibly, as a paramagnetic species, it increases intersystem crossing of the excited states of phenothiazine. On the basis of molecular models the proximity between the iron of ferricytochrome and phenothiazine is estimated to be over 20 Å. 相似文献
13.
The effect of pretreatment with phenobarbitone, rifampicin, β-naphthoflavone, antipyrine and spironolactone on the irreversible binding of ethynyloestradiol to guinea pig liver microsomes has been examined and the corresponding changes in microsomal P-450 content and cytochrome reductase activity measured. Rifampicin produced the greatest increase (220%) in irreversible binding while phenobarbitone produced the greatest increase in both microsomal P-450 content (172%) and cytochrome reductase activity (210%). There was no correlation of irreversible binding with either microsomal P-450 content or with cytochrome reductase activity. 相似文献
14.
M Erecińska R Oshino D F Wilson 《Biochemical and biophysical research communications》1980,92(3):743-748
[3H]-p-Azidophenacylbromide-(methyl-4-mercaptobutyrimidate)-cytochrome from was prepared and its properties determined. The radioactive photoaffinity-labeled cytochrome was linked by irradiation into a covalent complex with cytochrome oxidase. Analysis of the complex on SDS-polyacrylamide gels showed that cytochrome bound to one of the smaller subunits of cytochrome oxidase with an apparent molecular weight of 15,000. 相似文献
15.
NADPH-cytochrome reductase (NADPH-cytochrome reductase, EC 1.6.2.4), the flavoprotein which is responsible for the NADPH-dependent reduction of cytochromes P-450 in hepatic microsomes, has been localized immunohistochemically at the light microscopic level in rat liver. Localization was achieved through the use of sheep antiserum to rat hepatic microsomal NADPH-cytochrome reductase in an unlabeled antibody peroxidase-antiperoxidase technique. Parenchymal cells throughout the liver lobule were found to be stained positively for NADPH-cytochrome reductase, although the intensity of immunostaining was slightly greater in the centrilobular regions. Immunostaining for NADPH-cytochrome reductase was not detected in Kupffer cells, connective tissue cells, or in cells of the hepatic vasculature. 相似文献
16.
Bernard L. Trumpower 《Biochemical and biophysical research communications》1978,83(2):528-535
Mitochondrial ubiquinol-cytochrome reductase complex contains small amounts of succinate dehydrogenase. Estimates from electrophoresis indicate there is one dehydrogenase per eight complexes. This dehydrogenase transfers electrons to the - complex poorly, as judged by low succinate-ubiquinone and succinate-cytochrome reductase activities. Electron transfer to the - complex is restored by reconstitution of the complex with phospholipid. This phospholipid dependent restoration of electron transfer indicates that either reconstitutive activity of the dehydrogenase is preserved under conditions where electron transfer is absent, or that addition of phospholipid allows one dehydrogenase to transfer electrons to multiple - complexes. 相似文献
17.
Isolation and properties of the cytochrome B-C1 complex from Rhodopseudomonas sphaeroides 总被引:2,自引:0,他引:2
A highly purified and active cytochrome -1 complex has been isolated from the chromatophores of the photosynthetic bacteria R-26, through steps of Triton X-100 solubilization, salt fractionation and calcium phosphate column chromatography. The isolated enzyme complex catalyzes fully antimycin A sensitive oxidation of ubiquinol by cytochrome with a turnover number of 1500 per minute at 23° based on cytochrome 1. It contains 8.3 nmoles of cytochromes and 1 per mg protein and shows four polypeptides in the sodium dodecylsulfate polyacrylamide gel electrophoresis. 相似文献
18.
Rat liver microsomal NADH-cytochrome reductase activity is stimulated by 20 μM thyroxine . Thyroxine does not influence microsomal NADH-dichlorophenolindophenol reductase, NADPH-cytochrome reductase, or NADPH-dichlorophenolindophenol reductase activity. Stimulation of NADH-cytochrome reductase activity is not mediated by super-oxide and is likely due to enhanced reduction or oxidation of cytochrome 5. 相似文献
19.
Antimycin, when added to resolved succinate-cytochrome reductase complex in amounts sufficient to partially inhibit succinate-cytochrome reductase activity, causes a decrease in inhibition of the residual succinate-cytochrome reductase activity by 2-thenoyltrifluoroacetone. Antimycin has no effect on the inhibition of succinate-ubiquinone reductase activity by 2-thenoyltrifluoroacetone. We propose that antimycin increases the steady state concentration of ubisemiquinone in the reductase complex, and that 2-thenoyltrifluoracetone is competitive with ubisemiquinone. 相似文献
20.
Resonance Raman spectroscopy of cytochrome c oxidase and electron transport particles with excitation near the Soret band 总被引:3,自引:0,他引:3
I Salmeen L Rimai D Gill T Yamamoto G Palmer C R Hartzell H Beinert 《Biochemical and biophysical research communications》1973,52(3):1100-1107
We report the resonance Raman spectra of cytochrome oxidase, both solubilized and in electron transport particles using laser excitation near the Soret band. As in the spectra of other hemoproteins, such as cytochrome , the shape and intensity of a number of bands change when the oxidation state is varied. However, one of the hemes of solubilized cytochrome oxidase shows redox behavior which is anomalous. Spectra of electron transport particles are dominated by cytochrome oxidase. There are, however, definite differences between spectra of solubilized cytochrome oxidase and electron transport particles in the oxidized states. 相似文献