共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
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
3.
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
4.
Incubation of rat liver mitochondria with tetrahydropterin results in ATP production with a P:O ratio of 0.85, consistent with the entry of reducing equivalents into the mitochondrial electron transport chain at cytochrome . No evidence for an enzymatic reduction of cytochrome was found. The reduction of either soluble or mitochondrial cytochrome was not diminished by superoxide dismutase or anaerobic conditions, indicating that the reaction is not dependent on the autoxidation of the reduced pterin and the formation of an active species of oxygen. The experiments indicate a potential pathway for the production of ATP coupled to the oxidation of NADPH through the activity of NADPH-dependent pteridine reductases. 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.
F. Guerlesquin G. Bovier-Lapierre M. Bruschi 《Biochemical and biophysical research communications》1982,105(2):530-538
An acidic cytochrome c (Pi = 4.8) has been purified from Norway. Its molecular weight was estimated to be 26,000 but a monomeric form of 13,500 molecular weight has been obtained. The comparison of its amino acid composition and N terminal sequence has characterized this cytochrome as a new cytochrome, different from cytochrome c3 (Mr 13,000) and cytochrome c553(550) studied in the same organism. Its optical spectrum was similar to cytochrome c3 (Mr 13,000) accordingly it has 4 haems per subunit. The absence of absorption at 695 nm indicates that two histidine residues are implicated as fifth and sixth ligand for haem iron. This new cytochrome is homologous to the cytochrome C3 (Mr 26,000) previously described for and . 相似文献
7.
A cytochrome - cytochrome oxidase complex containing 0.8–1.0 moles of cytochrome per mole of cytochrome oxidase (heme a + a3) was isolated as described by Ferguson-Miller, S., Brautigan, D.L., and Margoliash E., J. Biol. Chem. , 1104 (1976). This complex was reacted with dithiobissuccinimidyl propionate, an 11 Å bridging bifunctional reagent, and the cross-linked products obtained were analyzed by two dimensional gel electrophoresis. Cytochrome was cross-linked to subunit II of cytochrome oxidase. Other cross-linked products were formed involving different subunits of cytochrome oxidase. These included I+V, II+V, III+V, V+VII, IV+VI and IV+VII. Experiments are also described using N,N′-bis(3-succinimidyloxycarbonylpropyl) tartarate. The major product formed with this 18 Å bridging bifunctional reagent was a pair containing II+VI. 相似文献
8.
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
9.
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
10.
C H Seiter R Margalit R A Perreault 《Biochemical and biophysical research communications》1979,86(3):473-477
Cytochrome was chemically coupled to cytochrome oxidase using the reagent 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) which couples amine groups to carboxyl residues. The products of this reaction were analyzed on 2.5–27% polyacrylamide gradient gels electrophoretically. Since cytochrome binds to cytochrome oxidase electrostatically in an attraction between certain of its lysine residues and carboxyl residues on the oxidase surface, EDC is an especially appropriate reagent probe for binding-subunit studies. Coupling of polylysine to cytochrome oxidase using EDC was also performed, and the products of this reaction indicate that polylysine, an inhibitor of the cytochrome reaction with oxidase, binds to the same oxidase subunit as does cytochrome , subunit IV in the gel system used. 相似文献
11.
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
12.
P. Bertrand M. Bruschi M. Denis J.P. Gayda F. Manca 《Biochemical and biophysical research communications》1982,106(3):756-760
Cytochrome c553 is a monohaemic c type cytochrome isolated from the sulfate reducing bacteria ,. Its midpoint potential value, determined by optical, EPR and polarographic studies is significantly lower than the midpoint potentials reported for other monohaemic cytochromes c (+ 10 mV instead of + 290 mV). In an attempt to study correlations between amino acid sequence, haem iron coordination and haem exposure in cytochromes c, cytochrome c553 is compared with mitochondrial and bacterial c type cytochromes. 相似文献
13.
The cytochrome oxidase (EC 1.9.3.1) of HB8 was isolated from the membrane fraction, and was highly purified. The oxidase contained heme and heme as the prosthetic groups. The purified preparation showed a single band in polyacrylamide gel electrophoresis, and three major polypeptides with apparent molecular weights of 52,000, 37,000 and 29,000 were observed in the presence of sodium dodecyl sulfate. The enzyme reacted rapidly with cytochrome c-552. The oxidation of cytochrome -555,549 by the enzyme was very slow, and was stimulated by the addition of cytochrome -552. The enzyme was highly stable to heat. 相似文献
14.
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
15.
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
16.
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
17.
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
18.
H A Sasame J R Gillette M R Boyd 《Biochemical and biophysical research communications》1978,84(2):389-395
An antibody prepared against purified rat liver NADPH-cytochrome reductase inhibited both the pulmonary and hepatic microsomal covalent binding of 4-ipomeanol as well as the respective NADPH-cytochrome reductase activities, findings which are consistent with previous studies which indicated the participation of cytochrome P450 in the metabolic activation of the toxin. An antibody prepared against purified rat liver cytochrome b5, which strongly inhibited both the rat hepatic and pulmonary NADH-dependent cytochrome reductases, and was inactive against the respective NADPH-dependent cytochrome reductases, had little effect on metabolic activation of 4-ipomeanol by hepatic microsomes, but strongly inhibited both the NADH-supported and the NADPH-supported pulmonary microsomal metabolism and covalent binding of the compound. These results suggest that metabolic activation of 4-ipomeanol involves a two-electron transfer in which transfer of the second electron via cytochrome b5 is rate-limiting in lung microsomes. 相似文献
19.
The proton translocating properties of cytochrome c oxidase in whole cells of Paracoccus denitrificans have been studied with the oxidant pulse method. quotients have been measured with endogenous substrates, added methanol and added ascorbate (+TMPD) as reductants, and oxygen and ferricyanide as oxidants. It was found that both the observed with ascorbate (+TMPD) as reductant, and the differences in proton ejection between oxygenand ferricyanide pulses, with endogenous substrates or added methanol as a substrte, indicate that the P. denitrificans cytochrome c oxidase translocates protons with a stoichiometry of . The results presented in this and previous papers are in good agreement with recent findings concerning the mitochondrial cytochrome c oxidase, and suggest unequal charge separation by different coupling segments of the respiratory chain of P. denitrificans. 相似文献
20.
The effects of exposure to two types of crude oil on microsomal mixed-function oxidase system components in livers of juvenile striped mullet () were investigated. Mullet were exposed for 4 days to emulsified Empire Mix or Saudi Arabian crude oils at an initial concentration of 75 ppm and an average of 1 ppm in the water column. Liver size was increased by about 50% following exposure to both oils. Since neither total hepatic protein nor microsomal protein increased as rapidly as did liver size, the concentrations of both were reduced following oil exposures. The proportion of microsomal protein to total hepatic protein or wet weight was not altered following crude oil exposure. Both cytochromes P-450 and 5 were induced following oil treatment. NADPH-dependent enzymes assayed with cytochrome and dichlorophenolindophenol as substrates showed increases in activity after exposure to Empire Mix crude oil but only the latter enzyme activity was increased on a microsomal protein basis following Saudi Arabian crude oil treatment. Activities of NADH cytochrome and NADH cytochrome 5 reductases appeared to vary with the protein level. However, since liver size was increased, oil-treated mullet had more of all parameters measured than did control mullet. Although the acute toxicity of Saudi Arabian crude oil to mullet is greater than that of Empire Mix crude oil, Empire Mix crude oil had greater inductive effects on microsomal oxidase components. 相似文献