| regulation and properties of an invertase from clostridium pasteurianum. | an intracellular invertase was induced in cultures of clostridium pasteurianum utilizing sucrose as its carbon source for growth. this enzyme synthesis could be repressed by the addition of fructose of a sucrose-growing culture. in contrast, invertase activity was not affected by the addition of glucose to sucrose-growing cells and this enzyme could be induced in a glucose-metabolizing culture by the addition of sucrose. this enzyme was purified 10.5-fold over the induced lese, ec 3.2.1.26) by s ... | 1975 | 140 |
| the internal-alkaline ph gradient, sensitive to uncoupler and atpase inhibitor, in growing clostridium pasteurianum. | 1. the intracellular ph was measured in growing clostridium pasteurianum with and acid-base equilibrium distribution method. 14cdimethyloxazolidinedione, 14methylamine and 14cacetic acid were used as "deltaph-indicators". during growth the extracellular ph decreased from 7.1 to 5.1; simultaneously the intracellular ph changed from 7.5 to 5.9. thus, the intracellular ph was more alkaline than the extracellular ph by 0.4 to 0.8 ph-units. 2. this ph gradient (interior alkaline) was abolished by the ... | 1975 | 237 |
| transport of molybdate by clostridium pasteurianum. | the transport of 99moo42- into dinitrogen-fixing cells of clostridium pasteurianum was investigated. transport of molybdate in this organism is energy dependent; sucrose is required in the minimal media, and the system is inhibited by the glycolysis inhibitors, naf, iodoacetic acid, and arsenate. the cells accumulate molybdate against a concentration gradient, and the uptake shows a marked dependence on temperature (optimum 37 c) and ph (optimum 6.0). the rate of molybdate uptake with increasing ... | 1975 | 364 |
| apparent oxidation-reduction potential of clostridium acidi-urici ferredoxin. effect of ph, ionic strength, and amino acid replacements. | the effects of ph and ionic strength on the midpoint reduction potential (emp) of clostridium acidi-urici ferredoxin were determined using hydrogen gas and hydrogenase. the emp of native ferredoxin at 24-25 degrees in 0.1 m tris-chloride buffer, ph 7.0, is--0.434 v. in the ph range examined, the emp becomes approximately 13 mv more negative per each ph unit increase. a plot of the log of ionic strength versus the apparent emp of ferredoxin in 0.1 m tris-chloride buffer, ph 7.5, was linear over t ... | 1976 | 3503 |
| proton-motive force in the obligately anaerobic bacterium clostridium pasteurianum: a role in galactose and gluconate uptake. | | 1975 | 6313 |
| non-heme iron proteins. the amino acid sequence of rubredoxin from desulfovibrio vulgaris. | a non-heme iron protein, rubredoxin has been isolated from the sulfate-reducing bacterium, desulfovibrio vulgaris, strain hildenborough. the complete amino acid sequence has been established. the 52 amino acid residues of the protein were aligned with the aid of tryptic and chymotryptic peptides and of a fragment produced by cleavage of the asn-gly bond (22-23) by hydroxylamine. the sequence of the first 30 residues of the molecule was determined using an automatic sequenator, after removal of t ... | 1976 | 7308 |
| electrochemistry of drug action i: electrooreduction of ferredoxins. | ferredoxin serves as an electron carrier in the oxidation-reduction system in anaerobic microorganisms, transferring electrons from a low potential donor to electron-accepting biochemicals. the anaerobicidal activity of some drugs may be due to their interference with the electron transport function of ferredoxin. two types of ferredoxins (isolated from clostridium pasteurianum and spinach) were studied, and their electrochemical reduction and biochemical properties were analyzed using a sensiti ... | 1976 | 10408 |
| reconstitution of a functional proton-translocating adenosine triphosphatase from the obligately anaerobic bacterium clostridium pasteurianum. | | 1977 | 19311 |
| carbon monoxide oxidation by methanogenic bacteria. | different species of methanogenic bacteria growing on co(2) and h(2) were shown to remove co added to the gas phase. rates up to 0.2 mumol of co depleted/min per 10 ml of culture containing approximately 7 mg of cells (wet weight) were observed. methanobacterium thermoautotrophicum was selected for further study based on its ability to grow rapidly on a completely mineral medium. this species used co as the sole energy source by disproportionating co to co(2) and ch(4) according to the following ... | 1977 | 21159 |
| the kinetics of methyl viologen oxidation and reduction by the hydrogenase from clostridium pasteurianum. | a mechanism for the reduction and oxidation of methyl viologen by clostridium pasteurianum hydrogenase (hydrogen:ferredoxin oxidoreductase, ec 1.12.7.1) is proposed. double reciprocal plots for methyl viologen reduction and oxidation at ph values 7.0-9.85 are linear, and the plots for reduction and oxidation are intersecting. such data are consistent with a mechanism in which the h2 and one methyl viologen bind (either in order or randomly) with subsequent reduction and release of the methyl vio ... | 1978 | 28770 |
| electron-paramagnetic-resonance studies on the redox properties of the molybdenum-iron protein of nitrogenase between +50 and -450 mv. | the midpoint potentials, em, for the oxidation of the characteristic e.p.r. signal with g values near 4.3, 3.7 and 2.01, of the nitrogenase mo-fe proteins from a number of bacteria were measured. they were 0mv for clostridium pasteurianum, -42mv for azotobacter chroococcum and azotobacter vinelandii, -95mv for bacillus polymyxa and -180mv for klebsiella pneumoniae mo-fe proteins at ph 7.9. the oxidations were thermodynamically reversible for the proteins from a. chroococcum, a. vinelandii and k. ... | 1978 | 30448 |
| isoelectric focusing of ferredoxins, flavordoxins and a rubredoxin. | isoelectric points of ferredoxins, flavodoxins and a rubredoxin from a range of sources were measured by electrofocusing over the ph range between 2.5 and 5.0 on thin layers of polyacrylamide gel. the ph gradient along the gel was measured directly by a surface electrode. the isoelectric points of the plant-type ferredoxins were between approx. 3.15 and 3.35, and those of the flavodoxins close to 3.5. ferredoxin, rubredoxin and flavodoxin from clostridium pasteurianum had isolectric points of th ... | 1978 | 31926 |
| oxidation of carbon monoxide in cell extracts of pseudomonas carboxydovorans. | extracts of aerobically, co-autotrophically grown cells of pseudomonas carboxydovorans were shown to catalyze the oxidation of co to co(2) in the presence of methylene blue, pyocyanine, thionine, phenazine methosulfate, or toluylene blue under strictly anaerobic conditions. viologen dyes and nad(p)(+) were ineffective as electron acceptors. the same extracts catalyzed the oxidation of formate and of hydrogen gas; the spectrum of electron acceptors was identical for the three substrates, co, form ... | 1979 | 33964 |
| the membrane adenosine triphosphatase of clostridium pasteurianum. effects of key intermediates of glycolysis on its atp phosphohydrolase activity. | | 1979 | 35367 |
| the proton-translocating adenosine triphosphatase of the obligately anaerobic bacterium clostridium pasteurianum. 1. atp phosphohydrolase activity. | 1. the cell-membrane atp phosphohydrolase of vegetatively grown clostridium pasteurianum was specifically mg2+-dependent, but demonstrated significant activity with gtp, ctp and utp. it displayed approximate michaelis-menten kinetics only in the presence of certain effectors (e.g. phosphoenolpyruvate, fructose 1,6-bis-phosphate) which decreased the km for atp (to below 2 mm) but also v, whilst extending to ph 5.8 the effective ph range of activity of the enzyme. 2. atp phosphohydrolase activity ... | 1979 | 39758 |
| the proton-translocating adenosine triphosphatase of the obligately anaerobic bacterium clostridium pasteurianum. 2. atp synthetase activity. | | 1979 | 39759 |
| molybdenum independence of nitrogenase component synthesis in the non-heterocystous cyanobacterium plectonema. | the cyanobacterium plectonema boryanum (iu 594-utex 594) fixes n2 only in the absence of combined n and of o2. we induced nitrogenase by transfer to anaerobic n-free medium and studied the effect of mo starvation on nitrogenase activity and synthesis. activity was first detected within 3 h after transfer by the acetylene reduction assay in controls, increasing for at least 25 h. cells grown on nitrate and mo and then transferred to n-free, mo-free medium produced 8% of the control nitrogenase ac ... | 1978 | 96092 |
| interaction of the nitrogenase components of anabaena cylindrica with those of clostridium pasteurianum. | | 1978 | 96817 |
| chelating agents protect hydrogenase against oxygen inactivation. | the effect of chelation on rate or air inactivation of hydrogenase from clostridium pasteurianum has been investigated. all chelating agents used, whether water-soluble or water-insoluble, afforded protection against oxygen inactivation. edta appeared to be the most effective. thus, in the absence of edta, hydrogenase in aqueous solution was nearly totally inactivated after 1 hour incubation in air, whereas 0.5 m edta (which did not affect significantly catalytic activity) allowed 41% retention ... | 1979 | 111712 |
| action of buytricin 7423 on clostridium pasteurianum: changes in intracellular adenosine triphosphate concentration. | | 1975 | 124278 |
| properties and function of clostridial membrane atpase. | atpase (atp phosphohydrolase, ec 3.6.1.3) was detected in the membrane fraction of the strict anaerobic bacterium, clostridium pasteurianum. about 70% of the total activity was found in the particulate fraction. the enzyme was mg2+ dependent; co2+ and mn2+ but not ca2+ could replace mg2+ to some extent; the activation by mg2+ was slightly antagonized by ca2+. even in the presence of mg2+, na+ or k+ had no stimulatory effect. the atpase reaction was effectively inhibited by one of its products, a ... | 1976 | 132964 |
| partial purification of a dicyclohexylcarbodi-imide-sensitive membrane adenosine triphosphatase complex from the obligately anaerobic bacterium clostridium pasteurianum. | the membrane adenosine triphosphatase complex of vegetatively growing clostridium pasteurianum, solublized with triton x-100, has been recovered as a significantly purified particulate preparation that is still sensitive to inhibition by dicyclohexylcarbodiimide and butyricin 7423. | 1976 | 133672 |
| nitrogenases from klebsiella pneumoniae and clostridium pasteurianum. kinetic investigations of cross-reactions as a probe of the enzyme mechanism. | in combination with the mo-fe protein of nitrogenase from klebsiella pneumoniae, the fe protein of nitrogenase from clostridium pasteurianum forms an active enzyme with novel properties different from those of either of the homologous nitrogenases. the steady-state rates of reduction of acetylene and h+ are 12% of those of the homologous system from c.pasteurianim. acetylene reductase activity exhibited an approx. 10min lag at 30 degrees c before the rate of reduction became linear, consistent w ... | 1976 | 134700 |
| [number of butyric acid bacteria belonging to the genus clostridium in the slimy sediments of volga reservoirs]. | the number of clostridium pasteurianum, cl. butyricum, and cl. acetobutylicum was determined in ooze deposits of the volga river reservoirs using enriched nutrient media. the bacterial number for the two former species was about 1 + 10(6) cells per 1 ml of ooze with a high content of easily assimilated organic substances, thus being by 1--3 orders of magnitude higher than for cl. pasteurianum on media without nitrogen. the bacterial number for cl. acetobutylicum was 0.1--1 + 10(3) cells per 1 ml ... | 1978 | 154608 |
| the iron electron-nuclear double resonance (endor) of 4-fe clusters in iron-sulfur proteins from chromatium and clostridium pasteurianum. | iron electron-nuclear double resonance (endor) measurements were made of the 4-fe clusters in oxidized chromatium high-potential iron-sulfur protein, dithionite-reduced high-potential iron-sulfur protein in 80% dimethylsulphoxide, fully reduced clostridium pasteurianum ferredoxin in aqueous solution and in 80% dimethylsulfoxide. the hyperfine couplings determined show that: i) the electron distribution in each case is nearly symmetric; ii) there are two types of iron in oxidized high potential i ... | 1975 | 164903 |
| nitrogenase from azotobacter chroococcum. purification and properties of the component proteins. | 1. a large-scale purification of the nitrogenase components from azotobacter chroococcum yielded two non-haem iron proteins, both of which were necessary for nitrogenase activity and each had a specific activity of approximately 2000 +/- 300 nmol of acetylene reduced/mg protein per min in the presence of sautrating amounts of the other. this procedure freed the mo-fe protein from a protein contaminant which had an electron paramagnetic resonance signal at g = 1.94. 2. both proteins were purified ... | 1975 | 173545 |
| on the iron-sulfur cluster in hydrogenase from clostridium pasteurianum w5. | hydrogenase, purified to an average specific activity of 328 mumol of h2 evolved/(min x mg of protein) from clostridium pasteurianum w5, was found to have 4-5 fe and 4-5 labile sulfur atoms per molecule of 60,000 molecular weight, in contrast with earlier reports of 12 fe per molecule. displacement of the iron-sulfur cluster from hydrogenase by thiophenol in 80% hexamethyl phosphoramide:20% h2o yielded the fe4s4 (thiophenyl)4 dianion according to absorption spectroscopy. electron paramagnetic re ... | 1975 | 174076 |
| physicochemical characterization of the four-iron-four-sulphide ferredoxin from bacillus stearothermophilus. | 1. a stable ferredoxin was prepared from bacillus stearothermophilus and purified by chromatography on deae-cellulose and by electrophoresis. 2. the minimum molecular weight determined from the amino acid composition was about 7900 and this was in reasonable agreement with a value of 8500 determined by polyacrylamide-gel electrophoresis. the ferredoxin contained four iron atoms and four labile sulphide groups per molecule. 3. the optical absorption, optical-rotatory-dispersion and circular-dichr ... | 1975 | 174558 |
| oxidation-reduction properties of several low potential iron-sulfur proteins and of methylviologen. | apparent oxidation-reduction potentials at ph 7.0 and 25 degrees c were determined using the h2-hydrogenase system with ferredoxins from the following sources: clostridium pasteurianum, -403 mv; c tartarovorum, -424 mv; c. acidi-urici, -434 mv; peptococcus aerogenes, -427 mv; chromatium d, -482 mv (ph 8.0); b. polymyxa, fd i, -377 mv, and fd ii, -422 mv; and spinach, -428 mv. the ph dependence of these values was variable, ranging from -2 to -24 mv/ph unit increase for different ferredoxins. ove ... | 1976 | 181047 |
| purification and properties of paramagnetic protein from clostridium pasteurianum w5. | the purification to homogeneity of the non-heme iron protein, sometimes referred to as either "red protein" or "paramagnetic protein", from clostridium pasteurianum w5 extracts is described and its physicochemical properties studied. this paramagnetic protein (g= 1.94) has a molecular weight of about 25000 and contains two iron and two acid-labile sulfur atoms per mol of protein. its midpoint potential at ph 7.5, as determined by electron paramagnetic resonance titration, is -300 mv. optical cir ... | 1976 | 181066 |
| the iron-sulfur centers and the function of hydrogenase from clostridium pasteurianum. | hydrogenase from c. pasteurianum is an iron-sulfur protein containing at least two tetrameric iron-sulfur centers. information on the structure of the remaining iron atoms must await future investigation. although the epr spectra of dithionite-reduced hydrogenase and eight-iron fd showed some similarity, the cd spectra clearly indicated a difference. the tetrameric iron-sulfur centers of hydrogenase were shown to undergo redox changes when hydrogenase was oxidized or reduced. however, no evidenc ... | 1976 | 183483 |
| direct assignment of the cysteinyl, the slowly exchangeable, and the aromatic ring 1h nuclear magnetic resonances in clostridial-type ferredoxins. | we have directly assigned the 1h nmr corresponding to the cysteinyl protons, the slowly exchangeable protons, and the aromatic ring protons in the 1h nmr spectrum of clostridium acidi-urici ferredoxin by isotopic labeling and 13c nmr decoupling techniques. we also show that the resonance pattern in the 8- to 20-ppm (from 2,2-dimethyl-2-sialapentanesulfonic acid) region of the 1h nmr spectra of oxidized clostridium acidi-urici, clostridium pasteurianum, clostridium perfringens, and peptococcus ae ... | 1977 | 191457 |
| partial purification of ferredoxin from ruminococcus albus and its role in pyruvate metabolism and reduction of nicotinamide adenine dinucleotide by h2. | extracts of ruminococcus albus were not able to convert pyruvate to acetyl phosphate, co2, and h2 after passage through a diethylaminoethyl (deae)-cellulose column. activity was restored by a brown protein fraction eluted from the column with 0.4 m cl-. the protein was partially purified and shown to have the spectral and biological characteristics of ferredoxin. r. albus ferredoxin, clostridium pasteurianum ferredoxin, and methyl viologen restored activity for pyruvate decomposition by deae-cel ... | 1977 | 195928 |
| purification and properties of hydrogenase from clostridium pasteurianum. | | 1978 | 213683 |
| nitrogenase x: mössbauer and epr studies on reversibly oxidized mofe protein from azotobacter vinelandii op. nature of the iron centers. | under anaerobic conditions the molybdenum-iron protein (mofe protein) from azotobacter vinelandii can be reversibly oxidized with thionine. electron paramagnetic resonance studies reveal that the oxidation proceeds in two distinct phases: the mofe protein can be oxidized by four electrons without loss of the epr signal from the s = 3/2 cofactor centers. a second oxidation step, involving two electrons, leads to the disappearance of the cofactor epr signal. in order to correlate the events during ... | 1978 | 215215 |
| determination of cooperative interaction between clusters in clostridium pasteurianum 2 (4fe-4s) ferredoxin. | the effect of reducing one 4fe-4s cluster in clostridium pasteurianum 2 (4fe-4s) ferredoxin on the reduction potential of the unreduced cluster has been investigated. while such an effect is suggested by both the x-ray structure of peptococcus aerogenes 2 (4f-4s) ferredoxin and the polypeptide conformational change on reduction present in clostridial-type 2 (4fe-4s) ferredoxins, present studies indicate that cluster-cluster cooperative interaction is not strong enough to be of functional importa ... | 1979 | 220247 |
| oxidative inactivation of the molybdenum-iron-protein component of nitrogenase from clostridium pasteurianum. | the sensitivity of the molybdenum-iron(mofe)-protein of clostridium pasteurianum nitrogenase toward oxidation has been studied by determining the enzymatic activity of this component after incubating it anaerobically in ferricyanide solutions of various oxidizing strengths (as measured by their oxidation potentials). it was found that the mofe-protein remains active at potentials up to +350 mv (vs. standard hydrogen electrode) but becomes readily inactivated at more oxidizing potentials, after a ... | 1979 | 228173 |
| iron-sulfur clusters in the molybdenum-iron protein component of nitrogenase. electron paramagnetic resonance of the carbon monoxide inhibited state. | carbon monoxide inhibits reduction of dinitrogen (n2) by purified nitrogenase from azotobacter vinelandii and clostridium pasteurianum in a noncompetitive manner (kii and kis = 1.4 x 10(-4) and 4.5 x 10(-4) and 7 x 10(-4) atm and 14 x 10(-4) atm for the two enzymes, respectively). the onset of inhibition is within the turnover time of the enzyme, and co does not affect the electron flux to the h2-evolving site. the kinetics of co inhibition of n2 reduction are simple, but co inhibition of acetyl ... | 1979 | 228701 |
| the electron spin relaxation of the electron acceptors of photosystem i reaction centre studied by microwave power saturation. | photosystem i particles from spinach were reduced by illumination at 77 k. under these conditions the one-electrom transfer from p-700 resulted in a reduction of only one acceptor molecule of the reaction centre. the epr signals at g=2.05, 1.94 and 1.86 were attributed to reduced centre a and the smaller signals at g=2.07, 1.92 and 1.89 to reduced centre b. reduction of both centres by dithionite in the dark lead to signals at g=2.05, 1.99, 1.96, 1.94, 1.92 and 1.89. thus, the features at g=2.07 ... | 1979 | 228715 |
| stable isotope fractionation by clostridium pasteurianum. 1. 34s/32s: inverse isotope effects during so4-2- and so3-2- reduction. | during growth on minimal salts--sucrose media supplemented with various concentrations (10-4-10-2 m) of sodium sulfate, clostridium pasteurianum grew at a normal rate and only evolved sulfide in late stages of growth on 10-2 m so4-2-. the evolved sulfide was slightly enriched in 34s as compared to the medium sulfur. on the other hand, sulfide was evolved during growth on all concentrations of sulfite tested. large normal and inverse isotopic effects were observed in the evolved sulfide during so ... | 1975 | 234781 |
| psychrophilic, mesophilic, and thermophilic triosephosphate isomerases from three clostridial species. | triosephosphate isomerase was purified to homogeneity as judged by analytical gel electrophoresis from clostridium sp. strain 69, clostridium pasteurianum, and c. thermosaccharolyticum, which grow optimally at 18, 37, and 55 c, respectively. comparative studies on these purified proteins showed that they had the same molecular weight (53,000) and subunit molecular weight (26,500). they were equally susceptible to the active site-directed inhibitor, glycidol phosphate. however, their temperature ... | 1975 | 235509 |
| kinetics and properties of beta-ketothiolase from clostridium pasteurianum. | 1. beta-ketothiolase of clostridium pasteurianum was purified 130-fold by ammonium sulphate fractionation and by column chromatography using deae-sephadex a-50 and hydroxylapatite. subjected to gel electrophoresis beta-ketothiolase revealed two distinct bands; by isoelectric focusing two enzymes with isoelectric points at ph 4.5 and 7.6 were separated. as established by sucrose density gradient centrifugation the molecular weight of both enzymes was found to be 158000. 2. the condensation reacti ... | 1975 | 240336 |
| the active species of 'co2' utilized by reduced ferredoxin:co2 oxidoreductase from clostridium pasteurianum. | reduced ferredoxin:co2 oxidoreductase (co2 reductase) from clostridium pasteurianum catalyzes the reduction of 'co2' to formate with reduced ferredoxin, an isotopic exchange between 'co2' and formate in the absence of ferredoxin, and the oxidation of formate to 'co2' with oxidized ferredoxin. the active species of 'co2', i.e. co2 or hco3 (h2co3), utilized by the enzyme was determined. the method employed for the species identification was that of copper et al. (1968). both 'co2' reduction to for ... | 1975 | 240689 |
| reduced ferredoxin: co2 oxidoreductase from clostridium pasteurianum. effect of ligands to transition metals on the activity and the stability of the enzyme. | reduced ferredoxin: co2 oxidoreductase (co2-reductase) from clostridium pasteurianum catalyzes the reduction of co2 to formate at the expense of reduced ferredoxin, an isotopic exchange between co2 and formate in the absence of ferredoxin, and the oxidation of formate to co2 with oxidized ferredoxin. the three activities were found to be equally affected by monovalent anions known to be ligands to transition metals: the enzyme was reversibly inhibited by azide (ki = 0.004mm), cyanate (ki = 0.3 m ... | 1975 | 241689 |
| identification of the iron-sulfur center in trimethylamine dehydrogenase. | trimethylamine dehydrogenase [trimethylamine:(acceptor) oxidoreductase (demethylating), ec 1.5.99.7] from a facultative methylotroph bacterium has a molecular weight of 147,000 and contains two types of prosthetic groups, one a covalently bound organic chromophore of uncertain structure and the other containing iron and labile sulfur (s*). the structure of the fe-s* center has been investigated by reactions of the enzyme with sodium mersalyl, o-xylyl-alpha,alpha'-dithiol, and p-methoxybenzenethi ... | 1977 | 265519 |
| a rationale for stabilization of oxygen-labile enzymes: application to a clostridial hydrogenase. | a general procedure for stabilization of o2-labile enzymes exploiting "salting out" of oxygen from the microenvironment in the molecular layers immediately adjacent to charged surfaces of polyionic solid adsorbents has been developed. empirical verification of this rationale is provided. the half-life of air inactivation of the o2-labile hydrogenase (ec 1.12.7.1) from clostridium pasteurianum is increased 20- to 25-fold simply by adsorption (noncovalent binding) in dilute tris.hcl buffer on comm ... | 1978 | 278979 |
| cluster characterization in iron-sulfur proteins by magnetic circular dichroism. | we report magnetic circular dichroism (mcd) spectra of 4-fe iron-sulfur clusters in the iron-sulfur proteins chromatium high-potential iron protein (hipip), bacillus stearothermophilus ferredoxin and clostridium pasteurianum ferredoxin. the mcd is found to vary significantly with cluster oxidation state but is relatively insensitive to the nature of the protein. the spectra obtained are compared with the corresponding spectra of iron-sulfur proteins containing 2-fe clusters. it is concluded tha ... | 1978 | 281679 |
| identification of iron-sulfur centers in the iron-molybdenum proteins of nitrogenase. | the core extrusion method has been applied to the determination of the type ([2fe-2s], [4fe-4s]) and number of iron-sulfur centers in the femo proteins of the nitrogenases from clostridium pasteurianum and azotobacter vinelandii. the method involves extrusion with o-xylyl-alpha, alpha'-dithiol, ligand exchange of the extrusion products with p-cf3c6h4sh (rfsh), and identification and quantitation of the resultant [fensn(srf)4]2- complexes (n = 2,4) by 19f nmr spectroscopy. in hexamethylphosphoram ... | 1979 | 291915 |
| choice of liquid, semisolid, or soil suspension media: an important factor modifying the effect of pesticides on the nitrogenase (c2h2) activity of clostridium pasteurianum, azotobacter chroococcum, and spirillum lipoferum beijerinck. | | 1979 | 295269 |
| the interaction of polymeric viologens with hydrogenases from desulfovibrio desulfuricans and clostridium pasteurianum. | the interaction between hydrogenases from either desulfovibrio desulfuricans or clostridium pasteurianum and electron donors methyl viologen or polymeric viologens was examined. extracts from each organism contained a single gel electophoretic band of active hydrogenase. the hydrogenase of d. desulfuricans was much more stable than that of cl. pasteurianum. with methyl viologen apparent km and vm values were 0.5 mm and 0.62 mumole h2/min per milligram protein for the cl. pasteurianum and 0.7 and ... | 1979 | 396014 |
| isolation of an iron-molybdenum cofactor from nitrogenase. | a method for the isolation of an iron-molybdenum cofactor (femoco) from component i of nitrogenase is described. this method is used to isolate femoco from aerobic, anaerobic, facultative, and photosynthetic nitrogen-fixing organisms. the fe/mo ratio in the femoco from azotobacter vinelandii and clostridium pasteurianum is 8:1. the femoco contains six atoms of acid-labile sulfide per eight fe atoms. crystalline component i from a. vinelandii contains 2 mo, 33 fe, and 27 acid-labile sulfide atoms ... | 1977 | 410019 |
| ferredoxin degradation in growing clostridium pasteurianum during periods of iron deprivation. | clostridium pasteurianum was grown in batch cultures on media with an initial iron concentration of 10 micron. the uptake of iron and the synthesis of ferredoxin was followed. all the iron present in the medium was taken up by the cells before 50% of the final cell density was attained. the bacteria then continued to grow in the complete absence of exogenous iron. ferrodoxin was synthesized during growth until the exogenous iron concentration dropped below 1 micron. during growth in the absence ... | 1979 | 426601 |
| evidence for ammonia translocation by clostridium pasteurianum. | | 1979 | 435301 |
| structural homologies in alanine-rich acidic ribosomal proteins from procaryotes and eucaryotes. | the amino acid composition and amino-terminal sequence have been determined for the alanine-rich, acidic ribosomal 'a' protein (equivalent to escherichia coli l7/l12) from three procaryotic cell types that live under extreme environmental conditions (arthrobacter glacialis, clostridium pasteurianum, and bacillus stearothermophilus) as well as from wheat germ, a eucaryote source. these data are compared with previously published 'a' protein sequences from other procaryotes and eucaryotes. all the ... | 1979 | 476516 |
| thiosulfate formation and associated isotope effects during sulfite reduction by clostridium pasteurianum. | during growth of clostridium pasteurianum on sulfite, approximately half the sulfite was reduced to sulfide and half to thiosulfate. sulfide was enriched in 32s or 34s at different stages of growth and thiosulfate was enriched in 32s, particularly in the sulfane atom. it is suggested that thiosulfate in these bacterial cultures arose from a secondary chemical reaction. the chemical formation of thiosulfate from sulfide and sulfite was also accompanied by sulfur isotope fractionation. the implica ... | 1979 | 476549 |
| mechanism of formation, spectrum and reactivity of half-reduced eight-iron clostridium pasteurianum ferredoxin in pulse-radiolysis studies and the non-co-operativity of the four-iron clusters. | reduction of fully oxidized clostridium pasteurianum 8-feox.,ox. ferredoxin by using pulse-radiolysis techniques yields the half-reduced species 8-feox.,red. ferredoxin. the subsequent oxidation of 8-feox.,red. ferredoxin with co(nh3)5cl2+ was studied. from a comparison with stopped-flow studies on the 2:1 co(nh3)5cl2+ oxidation of 8-fered.,red. ferredoxin to the 8-feox.,ox. form it is concluded that there is no redox co-operativity between the two 4-fe centres in these reactions. | 1979 | 534509 |
| studies on some characteristics of hydrogen production by cell-free extracts of rumen anaerobic bacteria. | hydrogen production was studied in the following rumen anaerobes: bacteroides clostridiiformis, butyrivibrio fibrisolvens, enbacterium limosum, fusobacterium necrophorum, megasphaera elsdenii, ruminococcus albus, and ruminococcus flavefaciens. clostridium pasteurianum and escherichia coli were included for comparative purposes. hydrogen production from dithionite, dithionite-reduced methyl viologen, pyruvate, and formate was determined. all species tested produced hydrogen from dithionite-reduce ... | 1977 | 558042 |
| the amino acid sequence of clostridium pasteurianum iron protein, a component of nitrogenase. i. tryptic peptides. | a total of 25 tryptic peptides was isolated from the s-beta-carboxymethyl derivative of clostridium pasteurianum iron protein (n2). in order to obtain the various peptides in pure state, a combination of gel permeation, cation and anion exchange column chromatographic methods, as well as various ascending paper chromatographic methods were adopted. sequence studies of the tryptic peptides were carried out mainly by a modified manual edman degradation procedure and also by automated analysis, car ... | 1977 | 561781 |
| the amino acid sequence of clostridium pasteurianum iron protein, a component of nitrogenase. ii. cyanogen bromide peptides. | a total of 10 cyanogen bromide peptides were isolated from the s-beta-carboxymethyl iron protein of nitrogenase. purification of these peptides was performed mainly by gel filtration on sephadex g-50; by ascending paper chromatography using the solvent system of pyridine, isoamyl alcohol, 0.1 m ammonium hydroxide; and also, in some cases, with additional steps such as anion exchange column chromatography on dowex 1-x2 or ascending paper chromatography in an acidic solvent system or by pyridine p ... | 1977 | 561782 |
| the amino acid sequence of clostridium pasteurianum iron protein, a component of nitrogenase. iii. the nh2-terminal and cooh-terminal sequences, tryptic peptides of large cyanogen bromide peptides, and the complete sequence. | | 1977 | 561783 |
| purification and properties of reduced ferredoxin: co2 oxidoreductase from clostridium pasteurianum, a molybdenum iron-sulfur-protein. | | 1978 | 639811 |
| metabolic products of microorganisms. 170. on the antibiotic activity of cladosporin. | cladosporin was isolated from the cultures of three species of the genus eurotium. cladosporin inhibited the growth of several fungi and at very low concentrations the growth of bacillus brevis and clostridium pasteurianum. bacillus subtilis and most other gram-positive bacteria were not sensitive. gram-negative bacteria and yeasts were not affected by concentrations up to 100 microgram/ml. dimethyl cladosporin showed only week activity against bacillus brevis with the minimal inhibitory concent ... | 1978 | 646581 |
| nitrogenase: the reaction between the fe protein and bathophenanthrolinedisulfonate as a probe for interactions with mgatp. | the reaction between the fe(ii) chelating agent, bathophenanthrolinedisulfonate, and the iron-sulfur cluster in the fe protein of nitrogenase from clostridium pasteurianum has been studied. this reaction is greatly accelerated by the presence of mgatp. analysis of the relationship between reaction rate and concentration of mgatp supports a model in which both of two binding sites for mgatp on the fe protein must be occupied before the protein undergoes a conformational change, allowing the iron- ... | 1978 | 656366 |
| oxidative inactivation of the fe-protein from clostridium pasteurianum nitrogenase. | | 1978 | 658421 |
| stable isotope fractionation by clostridium pasteurianum. 2. regulation of sulfite reductases by sulfur amino acids and their influence on sulfur isotope fractionation during so32- and so42- reduction. | in addition to an assimilatory sulfite reductase, studies of cultures of clostridium pasteurianum supplemented with methionine, cysteine, and 35so42- provides evidence for another reductase which is induced by so32-. this inducible reductase appears to be dissimaltory because of the copious sulfide production arising when the cells are grown on so32-. cysteine can repress the assimilatory sulfite reductase but does not affect the inducible reductase. during late logarithmic growth on 1 mm so42- ... | 1978 | 667738 |
| regulatory properties of the nitrogenase from rhodopseudomonas palustris. | ammonium salts, glutamine, asparagine, and urea cause an immediate inactivation (switch-off) of light-dependent acetylene reduction in intact cells of the photosynthetic bacterium rhodopseudomonas palustris. this effect is reversible showing the same kinetic pattern of inactivation and reactivation with all effector compounds. its duration depends on the amount of effector added to the cells. both nitrogenase components are found catalytically active in a cell-free preparation after enzyme switc ... | 1978 | 678011 |
| the evolution of protein sequences by repetitious gene duplication: clostridial flavodoxin. | internal regularities of amino acid sequences of flavodoxins, fmn-containing, low molecular weight flavoproteins, were statistically examined using the minimum mutation method. the sequence of clostridium pasteurianum flavodoxin shows statistically significant evidence of repetitious internal gene duplications at different levels of structure. peptide pairs with a low chance probabilitiy of occurrence were frequently observed at a shift of 5 residues. the pairs with the lowest chance probabiliti ... | 1978 | 691074 |
| assignment of the cysteinyl 13c nuclear magnetic resonances and comparison of other aliphatic amino acid resonances of clostridium acidi-urici, clostridium pasteurianum, and peptococcus aerogenes ferredoxins. | 13c nmr spectra of clostridium acidi-urici, clostridium pasteurianum, and peptococcus aerogenes ferredoxins show that some 13c resonances of the aliphatic amino acid residues are shifted significantly from their corresponding resonance positions in the spectra of model polypeptides or apoferredoxin. thirteen 13c resonances are shifted into the 80- to 120-ppm (from cs2) region, and have been assigned to the cysteinyl alpha and beta carbon atoms. the remaining shifted resonances in the 120- to 190 ... | 1978 | 701285 |
| isolation and properties of a unidirectional h2-oxidizing hydrogenase from the strictly anaerobic n2-fixing bacterium clostridium pasteurianum w5. | | 1978 | 728150 |
| circular dichroism and magnetic circular dichroism of iron-sulfur proteins. | circular dichroism (cd) and magnetic circular dichroism (mcd) spectra are reported for the 2-fe ferredoxins from pseudomonas putida and spirulina maxima, chromatium hipip, the 4-fe ferredoxin from bacillus stearothermophilus, and the 8-fe ferredoxin from clostridium pasteurianum. the spectral range spans the near-infrared, visible, and near ultraviolet. in all cases except oxidized 2-fe ferredoxins, electronic absorption is observed continuously from less than 5000 cm-1 to above 30,000 cm-1. the ... | 1978 | 728385 |
| nitrogenase: properties of the catalytically inactive complex between the azotobacter vinelandii mofe protein and the clostridium pasteurianum fe protein. | the catalytically inactive complex generated by the combination of the azotobacter vinelandii mofe protein (av1) and the clostridium pasteurianum fe protein (cp2) inhibits n2 reduction, c2h3 reduction, h+ reduction and atp hydrolysis catalyzed by the homologous nitrogenases. kinetic data indicate that the inactive complex consists of two molecules of cp2 to one molecule of av1, with values for the inhibitor constant in the range of 1--10 nm. inhibition of c. pasteurianum nitrogenase by av1 produ ... | 1978 | 728444 |
| isolation of thiomolybdate compounds from the molybdenum-iron protein of clostridial nitrogenase. | acid/base treatment of the molybdenum-iron protein of the nitrogenase from clostridium pasteurianum 25 yields low-molecular-weight compounds of molybdenum, which can be separated from the protein by gel chromatography. elementary analysis and spectral properties relate these compounds to thiomolybdate anions. it is proposed that in its native state nitrogenase contains a thio complex of molybdenum coupled to iron-sulfur clusters. | 1978 | 729574 |
| the apparent atp requirement for nitrogen fixation in growing klebsiella pneumoniae. | the apparent atp requirement for n2 fixation in klebsiella pneumoniae was high (the atp/n2 molar ratio was 29 when estimated in anaerobic glucose-limited chemostat cultures) compared with that determined previously in azotobacter chroococcum and in clostridium pasteurianum. the high value was probably not due to unfavourable temperature, phosphate concentration or ph. the apparent atp requirement for n2 fixation was probably no lower in 02-limited chemostat cultures than in anaerobic glucose-lim ... | 1976 | 784906 |
| specificity of bacterial ribosomes and messenger ribonucleic acids in protein synthesis reactions in vitro. | ribosomes from two gram-negative bacteria translated f2 rna, t4 early mrna, mrna from three gran-negative bacteria, and mrna from six gram-positive bacteria; ribosomes from three gram-positive bacteria translated mrna from the gram-positive strains, but did not translate the other mrnas. ribosomes from the gram-negative bacterium escherichia coli translated synthetic poly(u,g) but ribosomes from the gram-positive bacterium clostridium pasteurianum translated poly(u,g) very poorly, mrna from gram ... | 1976 | 816792 |
| quantitative extrusions of the fe4s4 cores of the active sites of ferredoxins and the hydrogenase of clostridium pasteurianum. | | 1977 | 830694 |
| comparative immunochemistry of bacterial, algal and plant ferredoxins. | 1. antibodies were produced in rabbits to the 4fe-4s ferrodoxins from bacillus stearothermophilus, the 2 [4fe-4s] ferredoxin from clostridium pasteurianum, and the 2fe-2s ferredoxins from the blue-green algia spirulina maxima, the green alga scenedesmus obliquus, and the higher plant beta vulgaris. the antibodies were tested for immunoprecipitation activity with seven bacterial, twelve blue-green algal, six eukaryotic algal and six higher plant ferredoxins. 2. antibodies to the bacterial ferredo ... | 1977 | 836867 |
| synthetic analogues of the active sites of iron-sulfur proteins. 15. comparative polarographic potentials of the [fe4s4(sr)4]2 -- ,3 -- and clostridium pasteurianum ferredoxin redox couples. | | 1977 | 850027 |
| evidence for separate enzymes of pyruvate decarboxylation and pyruvate synthesis in soluble extracts of clostridium pasteurianum. | additional evidence to that already presented (sauer, f. d., bush, r. s., and stevenson, i. l. (1976) biochim. biophys. acta 445, 518-520) suggests that pyruvate-ferredoxin oxidoreductase isolated from clostridium pasteurianum consists of two separate enzymes: (a) pyruvate lyase, which catalyzes the coa and electron acceptor-dependent decarboxylation of pyruvate, and (b) pyruvate synthase, which catalyzes the reduced ferredoxin-dependent carboxylation of acetyl-coa to pyruvate. the enzymes separ ... | 1977 | 856798 |
| phylogenetic studies of two rubredoxins from sulfate reducing bacteria. | the sequences of two rubredoxins isolated from the sulfate reducing bacteria: desulfovibrio vulgaris and desulfovibrio gigas have been elucidated. they have similar sequences but many more differences occur than would be expected from two bacteria of the same genus. of the 52 sites, only 37 are occupied by identical residues. the primary structures are compared with those of the anaerobic bacteria rubredoxins of clostridium pasteurianum, micrococcus aerogenes, pseudomonas oleovorans and peptostr ... | 1977 | 864718 |
| the low temperature magnetic circular dichroism spectra of iron-sulphur proteins. i. oxidised rubredoxin. | variable temperature magnetic circular dichroism spectra have been measured on oxidised clostridium pasteurianum rubredoxin. evidence has been obtained for the presence of two one-electron charge-transfer transitions, sulphur to ferric ion, in the region 15 000 to 28 000 cm-1. the first moment of the lower energy band is consistent with it being the orbital transition t1 non-bonding sulphur orbital, to the 2 e ferric d-orbital. the magnitude of the spin-orbit coupling constant in the lower excit ... | 1977 | 880309 |
| the iron-sulfur environment in rubredoxin. | the atomic environment around the iron site in the nonheme iron sulfur protein rubredoxin was studied by the extended x-ray absorption fine structure (exafs) technique. within experimental error, the fe-s bonds in oxidized clostridium pasteurianum rubredoxin are the same as in the analogue anion [fe(s2-o-xyl)2]-synthesized by holm. the average fe-s bond length is 2.267 +/- 0.003a and the root mean square deviation about this average due to structural disorder is 0.032 + 0.013 - 0.032. | 1977 | 890038 |
| the intracellular reserve polysaccharide of clostridium pasteurianum. | an amylopectinlike polysaccharide (granulose) was the only glucan produced in significant quantities by six wild-type strains of clostridium pasteurianum grown in glucose minimal medium. the intracellular polysaccharide granules laid down before sporulation contained only this amylopectin. no intracellular dextran was discovered in these wild-type strains, nor in a granulose-negative mutant strain of c. pasteurianum possessing an adp glucose pyrophosphorylase (ec2.7.7.27) but lacking a granulose ... | 1977 | 890606 |
| hydrogenase activity and the h2-fumarate electron transport system in bacteroides fragilis. | hydrogenase activity and the h(2)-fumarate electron transport system in a carbohydrate-fermenting obligate anaerobe, bacteroides fragilis, were investigated. in both whole cells and cell extracts, hydrogenase activity was demonstrated with methylene blue, benzyl viologen, flavin mononucleotide, or flavin adenine dinucleotide as the electron acceptor. a catalytic quantity of benzyl viologen or ferredoxin from clostridium pasteurianum was required to reduce nicotinamide adenine dinucleotide or nic ... | 1977 | 893348 |
| [microbiological characteristics of lake turali]. | the turali lake is a salt-water reservoir. the high salt content of water and ooze determine the microflora of the lake. the total bacterial number is lower in the summer than in the winter when the salt concentration in the lake decreases. the highest number of bacteria and sapropnytes is found in the spring. as a result of the high salt concentration in the water and ooze of the turali lake, the following physiological bacterial groups are partly or entirely absent: azotobacter, clostridium pa ... | 1977 | 909476 |
| the separation of pyruvate-ferredoxin oxidoreductase from clostridium pasteurianum into two enzymes catalyzing different reactions. | the ferredoxin requiring cleavage of pyruvate to acetyl-coa and co2 is catalyzed by pyruvate ferredoxin oxidoreductase (pyruvate:ferredoxin oxidoreductase (coa-acetylating):, ec 1.2.7.1). the same enzyme is thought to catalyze the reversal of this reaction, i.e. the synthesis of pyruvate from acetyl-coa and co2 in the presence of reduced ferredoxin. evidence is presented that the forward and reverse reactions are catalyzed not by one, but by two proteins that are clearly separable by sephadex g- ... | 1976 | 953041 |
| regulation of molybdate transport by clostridium pasteurianum. | the regulation of the molybdate (moo42-) transport activity of clostridium pasteurianum has been studied by observing the effects of nh3, carbamyl phosphate, moo42-, and chloramphenicol on the ability of cells to take up moo42-. compared with cells fixing n2, cells grown in the presence of 1 mm nh3 are greater than 95% repressed for moo42- transport. uptake activity begins to increase just before nh exhaustion (under ar or n2) and continues to increase throughout the lag period as cells shift fr ... | 1976 | 956118 |
| butyricin 7423: a bacteriocin produced by clostridium butyricum ncib7423. | butyricin 7423 is a trypsin-sensitive bacteriocin produced by clostridium butyricum ncib7423 and active against some other species of clostridium. it has a bactericidal but non-lytic action on growing cultures of clostridium pasteurianum. the primary action of butyricin 7423 appears to be at the cell membrane. thus treatment of c. pasteurianum with an excess of butyricin altered the permeability of its cell membrane, allowing the release of several metabolites and ions. efflux of rubidium ions f ... | 1976 | 956780 |
| sequence investigation of the clostridium pasteurianum nitrogenase: the partial amino acid sequence of azoferredoxin. | | 1976 | 961542 |
| the use of stable sulfur isotope labelling to elucidate sulfur metabolism by clostridium pasteurianum. | an unique isotope labelling experiment was conducted whereby mixtures of sulfate and sulfite of different isotopic compositions were metabolized by clostridium pasteurianum. the results showed during reduction of 1 mm so3= plus 1 mm so4=, essentially all evolved h2s arose from the sulfite whereas in the case of cellular sulfur, 85% was derived from sulfite and the remainder from sulfate. | 1976 | 985000 |
| [microflora of the gley process in soils of the carpathian region, reduction of iron by clostridium pasteurianum]. | | 1976 | 1012088 |
| synthetic analogs of active sites of iron-sulfur proteins: bis (o-xylyldithiolato) ferrate (iii) monoanion, a structurally unconstrained model for the rubredoxin fe-s4 unit. | to complete the set of synthetic analogs of the three recognized types of active sites in iron-sulfur redox proteins, the compound (et4n)[fe((sch2)2c6h4)2], derived from o-xylyl-alpha,alpha'-dithiol, has been prepared and its structure has been determined by x-ray diffraction. the bischelate anion contains a near-tetrahedral fe(iii)-s4 coordination unit with small rhombic distortions and all fe-s bond distances in the range 2.252-2.279 a. its electronic properties have been partially characteriz ... | 1975 | 1059080 |
| determination of the iron-sulfur distances in rubredoxin by x-ray absorption spectroscopy. | the high intensity x-ray flux from the synchrotron radiation at the stanford synchroton radiation project has been used to study the extended x-ray absorption fine structure (exafs) of the iron-sulfur protein peptococcus aerogenes rubredoxin. absorption measurements were made from 7080 ev, which is below the k-edge of iron, to about 650 ev above the edge and structure was obtained over the entire region. by means of a model iron-sulfur compound for evaluating the phase shifts, the variation of t ... | 1975 | 1060082 |
| nh---s hydrogen bonds in peptococcus aerogenes ferredoxin, clostridium pasteurianum rubredoxin, and chromatium high potential iron protein. | results from refinement of the crystal structures of p. aerogenes ferredoxin and c. pasteurianum rubredoxin determined by x-ray diffraction show that there are 15-18 nh---s bonds in the former and six in the latter with lengths in the range 3.1-3.9 a. earlier tritium exchange experiments are consistent with the presence of these hydrogen bonds in the ferredoxin structure and show that more peptide hydrogen atoms are available for exchange in apoferredoxin than in intact ferredoxin. four types of ... | 1975 | 1061073 |
| interactions of heterologous nitrogenase components that generate catalytically inactive complexes. | a unique method is described for inhibiting nitrogenase. when clostridium pasteurianum nitrogenase is assayed in the presence of the mo-fe protein of azotobacter vinelandii, all the characteristic activities of nitrogenase are inhibited. c. pasteurianum nitrogenase is unaffected by the fe protein of a. vinelandii. the fe protein, but not the mo-fe protein of c. pasteurianum, inhibits a. vinelandii nitrogenase. both inhibitions described result from the formation of an inactive complex of a. vine ... | 1976 | 1069989 |
| the use of 13c nuclear magnetic resonance of aromatic amino acid residues to determine the midpoint oxidation-reduction potential of each iron-sulfur cluster of clostridium acidi-urici and clostridium pasteurianum ferredoxins. | 13c nmr of the aromatic residues of clostridium acidi-urici [phe2]ferredoxin (a chemically modified ferredoxin in which a phenylalanyl residue replaces a tyrosyl residue) and clostridium pasteurianum ferredoxin permits one to distinguish and probe each iron-sulfur (fe7s7) cluster neighboring the aromatic residues within each protein. this is because the ring carbon resonance shifts of the phenylalanyl and tyrosyl residues can be distinguished. the 13c nmr results suggest that the midpoint oxidat ... | 1975 | 1116998 |
| purification of two clostridium bacteriocins by procedures appropriate to hydrophobic proteins. | two clostridocins distinguishable by their different modes of action on clostridium pasteurianum have been isolated, namely, butyricin 7423 found in cultures of clostridium butyricum ncib 7423 and perfringocin 11105 produced by clostridium perfringens type a, ncib 11105. both were trypsin-susceptible proteins which were soluble in concentrated aqueous ethanol and were able to bind large amounts of the nonionic detergent triton x-100. in the presence of triton x-100, butyricin 7423 behaved as a h ... | 1975 | 1137378 |
| characterization of two reserve glucans from clostridium pasteurianum. | the reserve glucans of c. pasteurianum, previously assumed to be a single polysaccharide, have been fractionated into two polysaccharides which resemble amylopectin and dextran. both polysaccharides are produced when cells are grown with sucrose, d-glucose, or d-fructose as carbon sources. | 1975 | 1148945 |
| role of molybdenum in dinitrogen fixation by clostridium pasteurianum. | the role of mo in the activity and synthesis of the nitrogenase components of clostridium pasteurianum has been studied by observing the competition of mo with its structural analogue w. clostridial cells when fixing n2 appeared strictly dependent upon the available mo, showing maximal n2-fixing activity at molybdate concentrations in the media of 10 mum. cells grown in media with 3 times 10(-6) mum mo, although showing good growth, had only 15% as much n2-fixing activity. in the presence of w t ... | 1975 | 1158853 |
| x-ray photoelectron spectra of iron-sulphur proteins. | the x-ray photoelectron spectra of the 2p, 3s and 3p levels of iron in oxidized clostridium pasteurianum ferredoxin indicate that the eight iron atoms in the molecule are indistinguishable. their magnetic state is indicated both by core polarization splitting of the 3s electrons, and by "shake-up' satellites on the 2p lines. similar satellites are observed in the 2p lines of reduced chromatium high-potential iron-sulphur proteins and oxidized spinach ferredoxin, indicating that there too the iro ... | 1975 | 1180907 |
| the active species of "co2" utilized in ferredoxin-linked carboxylation reactions. | the active species of "co2", i.e. co2 or hco-3(h2co3) utilized by enzymes catalyzing ferredoxin-linked carboxylation reactions was determined. the enzyme investigated was pyruvate synthase from clostridium pasteurianum (ec 1.2.7.1; pyruvate: ferredoxin oxidoreductase). data were obtained which were compatible with those expected if co2 is the active species. the dissociation constant (ks) of the enzyme-co2 complex was measured. at ph 7.2 ks for co2 of pyruvate synthase was found to be approximat ... | 1975 | 1190946 |