首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 718 毫秒
1.
  1. Two lactate dehydrogenases, L(+)- and D(–)- lactate cytochromec reductase, were extracted from the baker's yeast after disintegrationof the cells by a FRENCH press. They are separated by electrophoresison polyacrylamide gel and their activities were compared bycolor density of formazan, the reduction product of nitrobluetetrazolium.
  2. The ratio of L-lactate cytochrome c reductaseactivity to D-lactatecytochrome c reductase activity variedto a great extent, dependingon culture conditions. L-Lactatecytochrome c reductase waspredominant in resting cells; thereverse was the case withcells in early exponential stage ofthe growth.
  3. When the cells in exponential stage of growthwere aerated withoutnitrogen source, there occurred an intensiveincrease of L-lactatecytochrome c reductase, accompanied bythe decrease of D-lactatecytochrome c reductase.
  4. Effectsof inhibitors on the activity ratio of these two enzymeswereinvestigated. o-Phenanthroline, dinitrophenol, sodium azide,chloramphenicol, British antilewisite and antimycin A favored,in this order, the formation of L-lactate cytochrome c reductase.
(Received August 18, 1966; )  相似文献   

2.
  1. Cytochromes a1590, b560, c1554 and c1552 were isolated andpurifiedfrom a strain of Acetobacter suboxydans. The proceduresusedwere described in detail.
  2. The main cytochrome band at550-560 mµ in intact cellssplitted at liquid air temperatureinto two bands, 551 mµ(strong) and 559 mµ (weak).
  3. Optical and physiological properties of the four cytochromeswere investigated. Lactic dehydrogenase activity was found tobe associated with cytochrome c1554. The two c1-type cytochromes,especially cytochrome c1554, persisted in their reduced formafter the purification through many steps.
  4. By some combinationsof isolated components reconstruction ofthe oxygen uptake systemcould be realized.
  5. The oxygen-consuming activity of purifiedoxidase preparationswas accelerated by a-tocopherol but notby Emasoll 4130 andTween 80.
  6. Some discussions were made onthe nature of terminal oxidase,the role of cytochrome c1552in the electron-transport system,and persistence of reducedstate of c1-type cytochromes.
  7. A possible scheme of the electron-transferringsystem of Acetobactersuboxydans was presented.
(Received May 16, 1960; )  相似文献   

3.
  1. A phenolic pigment was extracted from baker's yeast. The pigmentis slowly autooxidizable, and rapidly oxidized with Rhus-laccaseor polyphenol oxidase and reduced by dithionite.
  2. The pigmentdissolved in ethylether had an absorption peak at258 mµ,shoulders at 289 and 382 mµ and a plateauat 450–500mµ. The difference spectrum between oxidizedand reducedforms of the pigment showed a wide plateau around500 mµ.
  3. The pigment supported the oxygen uptake by reconstructed enzymesystem: L-lactate, L-lactate cytochhrome c reductase and Rhuslaccaseor polyphenol oxidase. In its absence, no oxygen uptake tookplace. The pigment was replaced successfully with p-quinone,catechol and menadione, but not with ubiquinone. The sequenceof hydrogen transport can be represented: L-lactate L-lactatecytochrome c reductase "phenolic pigment" oxidase oxygen.
(Received August 11, 1967; )  相似文献   

4.
  1. Enzymic activities pertaining to Porphyra tenera cytochrome553 were investigated with cell-free extracts of a red alga,Porphyra tenera, and various fractions prepared therefrom.
  2. Thealgal extracts were found to be incapable, in the dark,of catalyzingoxidation of reduced cytochrome 553 at a ratesufficient toaccount for the respiratory oxygen-uptake in theintact cell.Oxidation of cytochrome 553 was highly acceleratedon illumination.The former reaction was found to be cyanide-sensitiveand thelatter, cyanide-insensitive. Both activities were foundto belocalized in the particulate fraction of the cell extract.
  3. Significantactivities of reduced pyridine nucleotide-cytochromereductasewere discovered in the soluble fraction of the cellextract,the reaction being two or three times faster with TPNHthanwith DPNH as electron donor. There was no reaction withsuccinatein the presence of cytochrome and 2,6–dichlorophenolindophenol.
  4. Porphyra tenera cytochrome 553 was shown to be localized inthe plastids of the algal cell.
  5. Possible functions of cytochrome553 in the algal metabolismwere discussed.
  相似文献   

5.
  1. Lactate oxidation system was investigated in Acetobacter suboxydans,which was found to have cytochromes a and b, but no cytochromec. Haemoprotein 558 was also found to exist.
  2. Carbon monoxideinhibited the lactate oxidation in the darkbut not in the light.WARBURG'S partition constant was estimatedto be 7.
  3. Additionof haemoprotein 558 noticeably enhanced the oxygenuptake bythe LDH preparation, which was obtained from bacterialcellsand partially purified.
  4. Haemoprotein 558 has protohaem asits prosthetic group. Notonly its absorption spectrum is reminiscentof that of peroxidase,but it also shows peroxidase-like reactivitywith some ligandswith a few exceptions.
  5. Ferrohaemoprotein558 reacts with oxygen, forming, at first,a complex, whichhas its SORET absorption peak at 423 mµ.The absorptionmaximum then shifts to 417 mµ, indicatinga transformationto another compound. One of these two productsis likely tobe the oxygenated ferro-haemoprotein 558.
  6. The mutual transformationbetween cytochrome B and haemoprotein558 is discussed.
(Received October 8, 1965; )  相似文献   

6.
Electron transport in theParacoccus denitrificans respiratory chain system is considerably more rapid when it includes the membrane-bound cytochromec 552 than with either solubleParacoccus c 550 or bovine cytochromec; a pool function for cytochromec is not necessary. Low concentrations ofParacoccus or bovine cytochromec stimulate the oxidase activity. This observation could explain the multiphasic Scatchard plots which are obtained. A negatively charged area on the back side ofParacoccus c which is not present in mitochondrialc could be a control mechanism forParacoccus reactions.Paracoccus oxidase and reductase reactions with bovinec show the same properties as mammalian systems; and this is true ofParacoccus oxidase reactions with its own soluble cytochromec if added polycation masks the negatively charged area. Evidence for different oxidase and reductase reaction sites on cytochromec include: (1) stimulation of the oxidase but not reductase by a polycation; (2) differences in the inhibition of the oxidase and reductases by monoclonal antibodies toParacoccus cytochromec; and (3) reaction of another bacterial cytochromec withParacoccus reductases but not oxidase. Rapid electron transport occurs in cytochromec-less mutants ofParacoccus, suggesting that the reactions result from collision of diffusing complexes.  相似文献   

7.
NAD-independent, mitochondrial -glycerophosphate dehydrogenaseof baker's yeast, Saccharomyces cerevisiae, was liberated fromcells and its nature was examined. Hydrogen acceptors, pH optimaand reaction rates with substrate and hydrogen acceptor of theenzyme were determined. A naturally occurring phenolic pigmentextracted from yeast cells was also found to function as aneffective hydrogen acceptor for the enzyme. Addition of FMNor FAD to the -glycerophosphate oxidation system largely acceleratedenzymatic activity, whereas the enzyme system was strongly blockedby SH-reagents. This suggests that the SH-group functions atan essential site. Clear-cut inhibition by antimycin A of electrontransfer to cytochrome c suggests the intermediation of cytochromeb. (Received December 13, 1968; )  相似文献   

8.
  1. Several kinds of a-hydroxysulfonates, the bisulfite additioncompounds of aldehydes and ketones, were found to inhibit thephotosynthetic carbon dioxide fixation of the barley and wheatseedlings, tobacco leaf and Chlorella cells. Bisulfite additioncompounds of glyoxal, glyoxylate and benzaldehyde were moreeffective in this respect than those of formaldehyde and acetaldehyde.
  2. The presence of -hydroxysulfonate causes an increase in ratiosof :14CO2 incorporated in glycolate and alanine, and a decreasein incorporation in serine, malate, isocitrate and citrate.It was inferred that these changes are caused by the blockingof the formation of glyoxylate through inhibition of glycolicacid oxidase by the poison.
  3. A reaction scheme was proposedto account for the above-statedresults, and the bearing ofthese findings on the possible roleof glycolic acid oxidasein the photosynthetic carbon dioxidefixation and in the formationof amino and organic acids wasdiscussed.
(Received December 8, 1961; )  相似文献   

9.
Using diploid strains of Saccharomyces cerevisiae and S. ellipsoideus,the following facts were found:
  1. Indole-3-acetic acid, 2,4-dichlorophenoxyacetic acid and -naphthaleneaceticacid produced stable variants differing in the cell form andin the response to the actions of auxin to elongate cells, toinduce respiration- deficient mutation and to promote sporulation.
  2. The auxins also produced stable variants differing in theabilityto form spores.
  3. Acetic acid had no above-menthionedactions of auxin.
  4. Spore-formation and cell elongation of someof auxin-inducedvariants were controlled by auxin.
Biological significance of the auxin-induced variation is discussedand the usefulness of some of these variants as experimentalmaterial for auxin physiology in general is pointed out. (Received November 1, 1966; )  相似文献   

10.
H. Asard  A. Bérczi 《Protoplasma》1998,205(1-4):37-42
Summary Plasma membrane (PM) vesicles were purified in parallel from the roots and shoots of 6-day-old etiolated bean (Phaseolus vulgaris L.) seedlings, grown in water culture at 25 °C, by aqueous polymer two-phase partitioning. The purity of PM fractions was determined by measuring the activity of known marker enzymes (vanadate-sensitive Mg-ATPase, 1,3--glycan synthase, latent ID-Pase, cytochromec oxidase, and antimycin-A-insensitive cytochromec reductase). NADH-(acceptor) oxidoreductase activities were determined with the following electron acceptors: ferricyanide, cytochromec, duroquinone, monodehydroascorbate, Fe3+-EDTA, and oxygen. Cytochromeb content was also determined. In general, results show that redox activities are higher in the root PM than in the shoot PM which follows the glycan synthase II (PM marker) pattern. The relative activities of the distinct redox enzymes measured (activity profile) are remarkably similar in the root and shoot PM preparations. The cytochromeb content and level of ascorbate reduction were also similar in both plant organs. However, the ratio of NADH-(acceptor) oxidoreductase activity to cytochrome content was signifcantly higher in roots when compared to the shoots.Abbreviations CCO cytochromec oxidase - CCR cytochromec reductase - GSII 1,3--glycan synthase - MF microsomal fraction - N-CC-OR NADH-cytochromec oxidoreductase - N-DQ-OR NADH-duroquinone oxidoreductase - N-FC-OR NADH-ferricyanide oxidoreductase - N-FE-OR NADH-Fe3+-EDTA oxidoreductase - N-MDA-OR NADH-monodehydroascorbate oxidoreductase - PM plasma membrane  相似文献   

11.
Cytochrome b561 from Rhodopseudomonas sphaeroides had cytochromec (c2) oxidase activity and a pH optimum at 6.0 for this activity.The activity was affected by the ionic strength of the reactionmixture. The apparent Km and maximal velocity (Vmax) valuesin the absence of addea salts were 14 µM and 120 nmoloxidized per min per mg protein for horse heart cytochrome c.Reduced horse heart cytochrome c was reoxidized in first-orderkinetics by this cytochrome b561. The specific activity was0.7 s–1 per mg protein at 20°C at the concentrationof 30 µMM cytochrome c. Activity was inhibited by KCN and NaN3, but not by antimycin.The addition of a low concentration of KCN to the cytochromeb561 produced a change in the absorption spectrum, evidencethat KCN interacts with the heme moiety of cytochrome b561.Results of this and preceeding studies show that the cytochromeoxidase (cytochrome "o") described earlier (Sasaki et al. 1970)is cytochrome b561. (Received May 16, 1983; Accepted September 8, 1983)  相似文献   

12.
The specificities for cytochrome c of the aa3-type cytochromec oxidase were studied with enzymes derived from Thiobacillusnovellas, Nitrobacter agilis, Paracoccus denitrificans and thecow in reaction with the cytochromes c from 5 prokaryotes and7 eukaryotes. The T. novellus enzyme reacted most rapidly withthe cytochromes c of Candida krusei, tuna and bonito as wellas T. novellus cytochrome c; the specificity for cytochromec of the N. agilis enzyme was similar to that of the T. novellusenzyme. The bovine enzyme reacted rapidly with all the eukaryoticcytochromes c tested. The P. denitrificans enzyme showed a specificitysimilar to that of the bovine enzyme, except that it reactedrapidly with P. denitrificans cytochrome c, while the bovineenzyme reacted with it very poorly. All four kinds of enzymesshowed an extremely limited reaction with Pseudomonas aeruginosacytochrome c. The amino acid composition of subunit I of the N. agilis enzymeresembled that of the bovine enzyme, while the compositionsof their subunits II were different. On the basis of these results,an evolutionary relationship between bacterial and eukaryoticenzymes was discussed. (Received May 21, 1981; Accepted August 20, 1981)  相似文献   

13.
Three kinds of discs were taken from tobacco leaves whose lowerepidermis had been peeled off, half-peeled or unpeeled. Therole of the epidermis and its relation to the kinetin effecton chlorophyll degradation during senescence were studied. Ourresults follow.
  1. Chlorophyll degradation due to kinetin was retarded only whenthe lower epidermis was present.
  2. The decrease in chlorophyllcontent in leaf discs on water duringsenescence was nearlyproportional to the size of the lowerepidermis attached tothe discs; i.e., unpeeled discs>half-peeleddiscs>peeleddiscs.
  3. Cellular fractions possessing activity which induceschlorophylldegradation were extracted from the isolated lowerepidermis(i, ii) and its acetone powder (iii): (i) L-2 fraction(1.14d1.16)was separated by stepwise sucrose density-gradientcentrifugationfrom the 10,000?g pellet of the cell homogenate.(ii) The A-fraction(M.W.5,000) was precipitated with 0–80%saturation ofammonium sulfate from 105,000 ? g supernatantof cell homogenateand eluted in the void volume by SephadexG-25 column chromatography.(iii) The fraction precipitatedwith 0–30% saturationof ammonium sulfate from the 105,000?gsupernatant, containeda large amount of DNA and its activityremained even if DNAwas removed.
  4. Activity was not retainedwhen the fractions were obtained fromisolated lower epidermispretreated with 2?10–5 M kinetinfor 2 hr in darknessat 25?C.
(Received June 3, 1976; )  相似文献   

14.
  1. An enzyme possessing a capacity of catalyzing reduction of thecopper protein, plastocyanin, with reduced pyridine nucleotides(TPNH-plastocyanin reductase) was isolated from Chlorella ellipsoidea.The procedures of purification and the properties of the purifiedenzyme are described.
  2. From the results of chromatographicand enzymic tests, the prostheticgroup of the enzyme was identifiedas FAD. No evidence was obtainedto indicate the participationof metal ions in the reaction.
  3. The enzyme utilizes both TPNHand DPNH as electron donors, butthe reaction is about 12 timesfaster with TPNH than with DPNH.
  4. The enzyme, with TPNH aselectron donor, catalyzes the reductionof Chlorella plastocyanin,cytochrome c, 2,6-dichlorophenolindophenol and oxygen in adecreasing order of reaction rate.The reaction with oxygenas electron acceptor was found to bemuch more strongly acceleratedby the addition of higher concentrationsof flavins as comparedwith the reaction with other acceptors.FAD and FMN added tothe reaction mixture are not appreciablyreduced.
  5. The propertiesof the enzyme are compared with those of alliedchloroplastenzymes reported by various investigators and thepossible roleof the new enzyme in photosynthesis is discussed.
(Received January 18, 1961; )  相似文献   

15.
The effects of several electron transport inhibitors on themagnitude and kinetics of cytochrome f oxidation induced byflash illumination were studied in the - and -band regions.On the flash excitation only a fraction of cytochrome f presentin the chloroplasts was oxidized with a half time of 0.1 to0.3 msec and then reduced with a half time of 10 to 25 msec. Dibromothymoquinone (DBMIB) at concentrations which severelysuppressed the reduction of cytochrome f approximately doubledthe magnitude of cytochrome f oxidation caused by a flash, mainlyby inducing an additional slow oxidation of cytochrome f witha half time longer than 1 msec. Enhancement of the cytochromef oxidation was also observed in the presence of bathophenanthroline.Such enhanced oxidation in duced by the two inhibitors was largelydiminished with the addition of reduced 2,6-dichlorophenolindophenolwhich accelerated cytochrome f reduction. In contrast, the inhibitionof cytochrome f reduction by 3-(3,4-dichlorophenyl)-1,1-dimethylurea(DCMU) was not associated with an increase in the magnitudeof cytochrome f oxidation. However, addition of DBMIB to theDCMU-poisoned chloroplasts enhanced cytochrome f oxidation,suggesting that this is related to a block of the electron transportbetween plastoquinone and cytochrome f. The results are explainedby assuming the occurrence of an electron carrier between plastoquinoneand cytochrome f. (Received May 10, 1978; )  相似文献   

16.
  1. 1. Analyses of cytochrome types in intact cells of aerobically-and anaerobically-grownPs. denitrificans indicated a higherratio of cytochrome c to cytochrome b in the former than inthe latter.
  2. 2. Anaerobically-grown cells contained about twotimes as muchcryptocytochrome c as did aerobically-grown cells.
  3. 3. Crystalline cryptocytochrome c obtained from the solublefraction of cell-free extracts of aerobically-grown cells manifestedthe same properties as cryptocytochrome c from anaerobically-growncells, i. e., absorption maxima, autooxidizability, redox potential,molecular weight, haem content, etc.
  4. 4. Cryptocytochrome cwas reversibly converted to a true haemochrometype spectrumby alcohols, detergents, carboxylic acid salts,guanidine saltor high pH values.
(Received December 16, 1968; )  相似文献   

17.
With the view to elucidate the role of myo-inositol in the ripeningprocess of rice grains, its distribution, formation and conversionwere studied.
  1. myo-Inositol in the ripening rice grains was fractionated intofree-, phosphate ester- and phosphoinositide-forms. At the earlystage of ripening, a considerable part of myo-inositol was foundin free state, and at the end of ripening stage the most partwas found in phosphate ester-state, phytic acid. The contentof phosphoinositide in the grains was low during the ripeningperiod.
  2. The occurrence of biosynthesis of myo-inositol inthe ripeningrice grains was confirmed by the observation ofincorporationof 14C into myo-inositol from 14C-sugars and itwas found, fromthe feeding experiment of myo-inositol- thatmyo-inositol doesnot undergo reactions further than phosphorylation.
  3. The feeding experiment of glucose-l-32P showed that the distributionpattern of 32P in different fractions of grain material wasthe same as that of 32P-phosphate, indicating that phytic acidis one of the final products of phosphorus metabolism in theripening rice grains.
  4. These results led to the assumptionthat myo-inositol mightact as an acceptor of phosphorus toremove inorganic phosphorusin favor of starch synthesis byphosphorylase.
(Received September 12, 1962; )  相似文献   

18.
  1. The effects of 3-(4'-chlorophenyl)-1, 1-dimethylurea (CMU)onthe fluorescence of photosynthetic pigments in vivo wereinvestigatedin blue-green, red and brown algae and in isolatedspinach chloroplasts.CMU caused an increase in steady statelevel of fluorescenceof chlorophyll a, but did not influencethe fluorescence ofphycobilins. The spectrum of the fluorescenceincrement hada peak at 685 m/µ and a shoulder at 730–740mµ.These two bands probably arise from chlorophyll a(Cf684) belongingto pigment system II.
  2. On excitation of chlorophylla in a red alga, Porphyra yezoensis,a fluorescence band witha peak at 720 mµ was observedbesides a shoulder at 685mµ. The 720 m band is inferredto arise from chlorophylla (probably, Cf-1) in pigment systemI.
  3. On addition of CMUto the algal cells, the induction of fluorescencewas modifiedto take a simple time course. The induction wasobserved onlywith respect to the fluorescence of chlorophylla, but not inthe fluorescence of phycobilins. The spectrumof the "transient"fluorescence showed two emission bands ofchlorophyll a at 685mµ and 740 mµ, and was quitesimilar in form tothe spectrum of the CMU-caused increase insteady state fluorescence.
  4. These facts were interpreted in terms of the correlation offluorescence of chlorophyll a and the photochemical reactionsof photosynthesis
(Received July 20, 1967; )  相似文献   

19.
(1) The distributions of four oxidative enzymes were studied in crude brain fractions. (2) Freeze-thaw cycle treatment and frozen storage of homogenate fractions gave apparent enhancement of cytochrome oxidase and NADH cytochrome c reductase activities. (3) Deoxycholate released cytochrome oxidase and NADH cytochrome c reductase activities from low-speed precipitates. The NADH diaphorase was enhanced to a small degree while NADPH cytochrome c reductase was not affected by deoxycholate. (4) Distilled water coupled with a single homogenization released trapped soluble enzymes and mitochondria and gave nearly maximal cytochrome oxidase activity as judged by deoxycholate treatment. The total distilled water activity of NADH cytochrome c reductase was much less than that of deoxycholate-stimulated fractions. The activities of other enzymes were not markedly affected by distilled water although their distribution was changed.  相似文献   

20.
DISTRIBUTION AND TURNOVER OF PHOSPHATE COMPOUNDS IN GROWING CHLORELLA CELLS   总被引:1,自引:0,他引:1  
  1. Using the Chlorella cells which had been uniformly labeled with32P, the distribution of phosphorus in various fractions ofcell material was investigated. Uniformly 32P-labeled Chlorellawas further grown in a P-free medium or in a standard "cold"medium, and the change of distribution of 32P (as well as theuptake of exogenous P) in various cell fractions was followed.
  2. Analysis of the 32P-labeled algal cells showed that the highestin P-content was the fraction of RNA followed by those of polyphosphates,lipid, nucleotidic labile phosphate compounds, DNA and protein(in decreasing order). ATP and ADP were found to be only minorfractions of the total labile phosphates.
  3. On incubating the3P-labeled alga in a P-free medium, the P.contentsin the fractionsof DNA, protein, lipid and ATP increased, thosein polyphosphatesand ADP decreased, and that in RNA remainedalmost unchanged.When the 32P-labeled alga was further grownin the normal "cold"medium, DNA and protein increased withthe expenditure of endogenous32P, but with practically no incorporationof external P. Inthe meantime the P in polyphosphates decreasedconsiderably,and the RNA fraction incorporated a large amountof externalP but only a little of endogenous32P.
  4. It was inferred that,under the experimental conditions of thepresent study, thephosphorus used in the syntheses of DNA andprotein was primarilytaken from polyphosphates, while thatused in the synthesesof RNA, phospholipid and polyphosphateswas, for the most part,taken from the extracellular P-source.
1A part of this paper was read at the Vth International Congressof Biochemistry, Moscow, August 10–16, 1961. (Received June 4, 1961; )  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号