| carcinogenic n-nitro-dimethylamine from the reaction of the analgesic amidopyrine and nitrite extracted from foodstuffs. | the reaction of the analgesic amidopyrine (100 mg) with nitrite extracted from cured meats and from spinach in varying degrees of spoilage was studied. unde physiological conditions the carcinogenic dimethylnitrosamine was formed at milligram levels at nitrite concentrations as low as 4 mg (in 175 ml extracted from 100 g boiled ham). the rate of decrease in concentration in the human stomach after ingestion of amidopyrine and of nitrite contained in boiled ham or in a broth from boiled ham was a ... | 1975 | 861 |
| isolation and some properties of nad+ reductase of the green photosynthetic bacterium prosthecochloris aestuarii. | nad+ reductase of the green photosynthetic bacterium prosthecochloris aestuarii was isolated and purified by ammonium sulfate fractionation, deae-cellulose column chromatography, and sephadex g-200 gel filtration. this enzyme is an fad-containing flavoprotein and has absorption maxima at 485 (shoulder0 452, 411, and 385 nm (the 411 nm band is due to cytochrome). the molecular weight of the enzyme as determined by gel filtration using sephadex g-200 is 119,000. the enzyme catalyzes the reduction ... | 1976 | 5430 |
| some properties of a microsomal oleate desaturase from leaves. | 1. when 1-14coleoyl-coa was incubated with a pea-leaf homogenate oleate was both incorporated into microsomal 3-sn-phosphatidylcholine and released as the unesterified fatty acid. the proportion of oleate incorporated into this phospholipid was dependent on the relative amounts of thiol ester and microsomal preparation present in reactions. 2. at the concentrations of microsomal preparation and 14coleoyl-coa used to study oleate desaturation the metabolism of the thiol ester was essentially comp ... | 1976 | 7242 |
| 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 |
| different molecular forms of d-ribulose-1,5-bisphosphate carboxylase from rhodopseudomonas sphaeroides. | ribulose-1,5-bisphosphate (rbu-p2) carboxylase isolated from rhodopseudomonas sphaeroides 2.4.1.ga was separated into two different forms by deae-cellulose column chromatography. both forms, designated peak i and peak ii have been purified to homogeneity by the criterion of polyacrylamide disc-gel electrophoresis. the peak i carboxylase has a molecular weight of 550,000, while the peak ii carboxylase is a smaller protein having a molecular weight of approximately 360,000. sodium dodecyl sulfate ... | 1977 | 14141 |
| phosphoribulokinase from nitrobacter winogradskyi: activation by reduced nicotinamide adenine dinucleotide and inhibition by pyridoxal phosphate. | co2 fixation by particle-free extracts from nitrobacter winogradskyi increased by addition of reduced nicotinamide adenine dinucleotide (nadh). ribulose-1,5-diphosphate, however, increased co2 fixation, even in the absence of nadh. phosphoribulokinase (ec 2.7.1.19) was the enzyme of nitrobacter extracts that was activated specifically by nadh. pyridoxal-5-phosphate inhibited both co2 fixation and nadh-activated phosphoribulokinase from nitrobacter. however, it did not affect phosphoribulokinase ... | 1977 | 15976 |
| adenosine-5'-phosphosulfate (aps) as sulfate donor for assimilatory sulfate reduction in rhodospirillum rubrum. | crude extracts of rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (35s) sulfate, (35s) adenosine-5'-phosphosulfate, and (35s) 3'-phosphoadenosine-5'-phosphosulfate. an enzyme fraction similar to aps-sulfotransferases from plant sources was purified 228-fold from rhodospirillum rubrum. it is suggested here that this enzyme is specific for adenosine-5'-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5'-phosphosulfate; 3'-phosphoadenosine ... | 1977 | 16577 |
| the stereospecificity of nitrate reductase for hydrogen removal from reduced pyridine nucleotides. | the stereospecificity of the hydrogen removal from reduced pyridine nucleotides catalyzed by nitrate reductase (nadh : nitrate oxidoreductase, ec 1.6.6.1, and nad(p)h : nitrate oxidoreductase, ec 1.6.6.2) was investigated. a high degree of enzyme purification was required to obtain conclusive results. improvements are described for the purification of nitrate reductase from chlorella fusca and from spinach (spinacea oleracea, l.) leaves. the latter enzyme is shown to contain a cytochrome. with h ... | 1977 | 16653 |
| purification and some properties of riboflavin synthetase from bacillus stearothermophilus atcc 8005. | a riboflavin synthetase was purified 51-fold from a thermophilic organism, bacillus stearothermophilus atcc 8005, that grew at 40 to 72 degrees c. some of the properties of the enzyme are: (i) its temperature optimum was 95 degrees c, and the activity was negligible below 40 degrees c; (ii) the arrhenius plot of the initial reaction rates was concave upward, with a break at 65 degrees c, and the apparent activation energies below and above 65 degrees c were 4.2 x 10(4) and 6.7 x 10(4) j/mol, res ... | 1978 | 25043 |
| the role of chloride ion in photosystem ii. i. effects of chloride ion on photosystem ii electron transport and on hydroxylamine inhibition. | 1. chloroplasts washed with cl--free, low-salt media (ph 8) containing edta, show virtually no dcmu-insensitive silicomolybdate reduction. the activity is readily restored when 10 mm cl- is added to the reaction mixture. very similar results were obtained with the other photosystem ii electron acceptor 2,5-dimethylquinone (with dibromothymoquinone), with the photosystem i electron acceptor fmn, and also with ferricyanide which accepts electrons from both photosystems. 2. strong cl--dependence of ... | 1978 | 26390 |
| enzyme reactions of atp studied by positional isotope exchange. | reversible gamma-po3 transfer in atp reactions can be recognized by exchange of 18o from the beta,gamma-bridge position to the beta-p-nonbridge positions: (see article). such intramolecular exchange is less demanding for the detection of the bond cleavage than the usual atp:adp isotope exchange because it does not require dissociation of bound adp from the intermediate complex. acyl phosphate intermediates are indicated for the glutamine synthetase and carbamyl-p synthetase reactions by their ex ... | 1978 | 31305 |
| crystalline reduced nicotinamide adenine dinucleotide phosphate-adrenodoxin reductase from pig adrenocortical mitochondria. essential histidyl and cysteinyl residues of the nadph-binding site and environment of the adrenodoxin-binding site. | pig nadph-adrenodoxin reductase was crystallized from pig adrenocortical mitochondria and its physicochemical properties were investigated. pig nadph-adrenodoxin reductase is a typical flavoprotein. its optical absorption spectrum showed peaks at 272, 377, and 450 nm in the oxidized form. the adrenodoxin reductase contained one fad per mol. the molecular weight was 49,000. the isoelectric points of the adrenodoxin reductase and its complex with adrenodoxin were 5.3 and 4.6, respectively. pig nad ... | 1978 | 32168 |
| bioavailability of cd to food crops in relation to heavy metal content of sludge-amended soil. | results of greenhouse and laboratory experiments on factors influencing uptake and accumulation of cd by economic crops are summarized.tolerance to cd is highly crop-specific. for example, 21 different economic crops were grown in pots filled with a calcareous soil treated with increasing amounts of cd. yields versus cd addition rate relations showed yield reductions to occur with cd sensitive plants (spinach, soybean, curlycress, and lettuce) at addition rates varying from 5 to 15 mug cd/g soil ... | 1979 | 39746 |
| localization of the tri- and digalactosyl diglyceride in the thylakoid membrane with serological methods. | trigalactosyl diglyceride was isolated from leaves of urtica dioica and characterized by thin layer chromatography, infrared spectroscopy and by its fatty acid composition. an antiserum to the trigalactolipid was obtained by immunization of rabbits. by means of inhibition experiments with oligosaccharides and mono- and digalactosyl glycerol it was demonstrated that the antibodies are directed towards the alpha-galactosyl-(1 leads to 6)-alpha-galactosyl-(1 leads to 6)-beta-galactosyl-(1 leads to ... | 1976 | 62464 |
| analyses of absorption and fluorescence spectra of water-soluble chlorophyll proteins, pigment system ii particles and chlorophyll a in diethylether solution by the curve-fitting method. | absorption and fluorescence spectra in the red region of water-soluble chlorophyll proteins, lepidium cp661, cp663 and brassica cp673, pigment system ii particles of spinach chloroplasts and chlorophyll a in diethylether solution at 25 degrees c were analyzed by the curve-fitting method (french, c.s., brown, j.s. and lawrence, m.c. (1972) plant physiol 49, 421--429). it was found that each of the chlorophyll forms of the chlorophyll proteins and the pigment system ii particles had a correspondin ... | 1978 | 96855 |
| [2-anilino-1,3,4-thiadiazoles, inhibitors of oxidative and photosynthetic phosphorylation (author's transl)]. | 2-anilino-1,3,4-thiadiazoles carrying various substituents in the 5-position as well as in the benzene-ring were synthesized. the compounds were tested with rat-liver-mitochondria and with spinach-chloroplasts and revelaed to be potent uncouplers of both, oxidative and photosynthetic phosphorylation, with pi50-values rangeing from 6.79 to 4.05. at higher concentrations all compounds are inhibitors of the hill-reaction. in mitochondria a fair correlation exists between pka of the acidic nh-group ... | 1975 | 125966 |
| ultrastructural changes in in vitro ageing spinach chloroplasts. | ultrastructural changes in in vitro ageing spinach chloroplasts have been studied in detail. prolonged storage caused swelling of the chloroplasts due to the increase in the thickness and spacing of the thylakoid membranes. the increase in the thickness of the membrane is partly accompanied by the release of lipids. addition of crystalline bovine serum albumin was found to stabilize the membrane structures. storage of the chloroplasts at 77 degrees k even though it resulted in complete breakage ... | 1976 | 132044 |
| cf1-dependent restoration of energy-linked reactions reconstituted with a hydrophobic protein from spinach chloroplasts. | | 1977 | 142483 |
| evidence for a catalytic function of the coupling factor 1 protein reconstituted with chloroplast thylakoid membranes. | the effects of tentoxin on the atpase activities of coupling factor 1 proteins (cf1) and photophosphorylation with isolated chloroplasts and chloroplasts reconstituted with coupling factor proteins have been examined. 1. the calcium-dependent atpase activities of coupling factors isolated from spinach, lettuce and nicotiana otophora are completely inhibited by tentoxin. the atpase activities of coupling factors isolated from nicotiana tabacum and nicotiana knightiana are not affected by tentoxin ... | 1978 | 147703 |
| synthetic inhibitors of adenylate kinases in the assays for atpases and phosphokinases. | 1. procedures are given for the syntheses of alpha,omega-dinucleoside 5'-polyphosphates as inhibitors of adenylate kinases. the following order for the ability of inhibiting pig muscle adenylate kinase was observed: ap5a greater than 1:n6-etheno-ap5a greater than ap6a greater than gp5a greater than ap4a greater than up5a. the synthesis of adenosine tetraphosphate, the starting material for ap5a, is also described. 2. one molecule of pig muscle adenylate kinase binds one molecule of ap5a. the dif ... | 1975 | 170110 |
| high and low reduction potential 4fe-4s clusters in azotobacter vinelandii (4fe-4s) 2ferredoxin i. influence of the polypeptide on the reduction potentials. | azotobacter vinelandii (4fe-4s)2 ferredoxin i (fd i) is an electron transfer protein with mr equals 14,500 and eo equals -420 mv. it exhibits and epr signal of g equals 2.01 in its isolated form. this resonance is almost identical with the signal that originates from a "super-oxidized" state of the 4fe-4s cluster of potassium ferricyanide-treated clostridium ferredoxin. a cluster that exhibits this epr signal at g equals 2.01 is in the same formal oxidation state as the cluster in oxidized chrom ... | 1975 | 170272 |
| classification of fructose-1,6-bisphosphate aldolases based on 18o retention in the cleavage reaction. | oxygen (18) was used as a mechanistic probe in the investigation of several different sources of fructose 1,6-bisphosphate aldolases (ec 4.1.2.13) which, due to differences in some physical and chemical properties, could not be clearly put in either class i or class ii. aldolases may be identified as belonging to a particular class on the basis of the amount of 180 retained in the dihydroxyacetone phosphate produced in the cleavage of [2-oxygen (18)] fructose 1,6-biphosphate. the mechanism of cl ... | 1975 | 170973 |
| on the nature of the iron sulfur cluster in a deuterated algal ferredoxin. | a protonated and a completely deuterated two-iron algal ferredoxin from synechococcus lividus have been studied by optical, electron paramagnetic resonance, electron-nuclear double resonance, proton magnetic resonance and mossbauer spectroscopies; temperature dependent magnetic susceptibility measurements are reported as well. these studies have confirmed the electron localized model of the active center in the two-iron ferredoxins, as previously deduced from studies of spinach ferredoxin, have ... | 1975 | 172131 |
| the distribution of pyrophosphatidic acid in nature. | the occurrence of a novel phospholipid, pyrophosphatidic acid, in the lipid extracts of yeasts (23 species), bacteria (e. coli), algae (chlorella), mammalia (human, rabbit, guinea pig, and mouse), insect (cockroach), fish (carp), mollusc (clam), and spermatophyta (spinach) was investigated. pyrophosphatidic acid was found exclusively in the lipid extracts of several kinds of yeast species, but not in other normal living species (animals, plants, and microorganisms) so far investigated. all of th ... | 1975 | 175047 |
| 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 |
| electron spin polarization in photosynthesis and the mechanism of electron transfer in photosystem i. experimental observations. | transient electron paramagnetic resonance (epr) methods are used to examine the spin populations of the light-induced radicals produced in spinach chloroplasts, photosystem i particles, and chlorella pyrenoidosa. we observe both emission and enhanced absorption within the hyperfine structure of the epr spectrum of p700+, the photooxidized reaction-center chlorophyll radical (signal i). by using flow gradients or magnetic fields to orient the chloroplasts in the zeeman field, we are able to influ ... | 1978 | 204369 |
| phosphoglycolate phosphatase. purification and properties. | phosphoglycolate phosphatase (ec 3.1.3.18) was purified 1500-fold from field-grown tobacco leaves by acetone fractionation, deae-cellulose and molecular sieve chromatography, and preparative polyacrylamide gel electrophoresis. preparations were judged 90 to 95% homogeneous by chromatography on deae-cellulose, polyacrylamide gel electrophoresis, and by isoelectric focusing. the highest specific activity obtained was 468 mumol of phosphate released/min/mg of protein. the native protein has a molec ... | 1978 | 204630 |
| multiple functions of thioredoxins. | reduced thioredoxins from microbial and plant cells, both of cytoplasmic or chloroplast origin, are interchangeable in stimulating such diverse enzyme activities as ribonucleoside diphosphate reductase (e. coli), paps sulfotransferase (synechococcus), and fructose-1,6-bis-phosphatase (from spinach) in vitro. it is suggested that reduced thioredoxins are unspecific, multifunctional cellular proteins while in contrast the oxidized froms require specific enzymes for their reduction. | 1978 | 212888 |
| 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 |
| 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 |
| further studies on the subunit structure of chromatium ribulose-1,5-phosphate carboxylase. | upon alkali exposure chromatium ribulose-1,5-bisphosphate carboxylase dissociates into constituent subunits, a catalytic oligomer of the larger subunit, a8, and monomeric form of the small subunit b. by sedimentation equilibrium molecular weights of the native enzyme and the catalytic oligomer produced by an alkali treatment were estimated to be 5.11 x 10 5 and 4.29 x 10 5, respectively. to provide information on reversibility of the dissociation by determining whether the enzymically inactive s ... | 1975 | 234018 |
| studies on indoleamine 2,3-dioxygenase. i. superoxide anion as substrate. | indoleamine 2,3-dioxygenase purified to apparent homogeneity from rabbit intestine was inhibited by scavengers for superoxide anion such as superoxide dismutase and 1,2-dihydroxybenzene-3,5-disulfonic acid (tiron). on the other hand, beta-carotene and 1,4-diazobicyclo-(2,2,2)-octane, scavengers for singlet oxygen, did not affect the enzyme activity significantly. the degree of inhibition of the dioxygenase by superoxide dismutase preparations from bovine erythrocytes, green peas, spinach leaves, ... | 1975 | 238993 |
| the effect of an antiserum to plastocyanin on various chloroplast preparations. | a monospecific antiserum to tobacco plastocyanin agglutinates stroma-free swellable chloroplasts from wild type tobacco, (nicotiana tobacum var. john william's broadleaf) from the tobacco aurea mutant su/su2, (nicotiana tabacum var. su/su2) from antirrhinum majus and spinach (spinacia oleracea). in this condition the antiserum inhibits linear photosynthetic electron flow in tobacco and spinach chloroplasts. this inhibition of electron transport as well as the agglutination are not observed if th ... | 1975 | 240237 |
| 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 |
| subcellular localization of acyl carrier protein in leaf protoplasts of spinacia oleracea. | this communication demonstrates that all de novo fatty acid biosynthesis in spinach leaf cells requires acyl carrier protein (acp) and occurs specifically in the chloroplasts. antibodies raised to purified spinach acp inhibited at least 98% of malonyl coa-dependent fatty acid synthesis by spinach leaf homogenates. therefore, the presence of acp in a compartment of the spinach leaf cell would serve as a marker for de novo fatty acid biosynthesis. a radioimmunoassay capable of detecting 10(15) mol ... | 1979 | 286305 |
| magnetic field-induced increase of the yield of (bacterio)chlorophyll emission of some photosynthetic bacteria and of chlorella vulgaris. | in photosynthetic bacteria, in which the iron-ubiquinone complex x is prereduced, a magnetic field induces an increase of the emmission yield, which is correlated with the decrease in reaction center triplet yield reported previously (hoff, a.j., rademaker, h., van grondelle, r. and duysens, l.n.m. (1977) biochim. biophys. acta 460, 547--554). our results support the hypothesis that under these conditions charge recombination of the oxidized primary donor and the reduced primary acceptor predomi ... | 1979 | 312658 |
| activation of ribulose 1,5-bisphosphate carboxylase from rhodopseudomonas sphaeroides: probable role of the small subunit. | the activation properties of the form i and form ii ribulose 1,5-bisphosphate carboxylases from rhodopseudomonas sphaeroides were examined. both enzymes have a requirement of mg2+ for optimal activity. mn2+, ni2+, and co2+ can also support activity of the form i enzyme, whereas only mn2+ can substitute for mg2+ with the form ii enzyme. the effect of different preincubations on the carboxylase reaction was also examined. both enzymes exhibited a lag when preincubated with other than mg2+ and co2 ... | 1979 | 316430 |
| isolation and characterisation of 14-s rna from spinach chloroplasts. | 14-s rna was purified from spinach chloroplasts. it has a molecular weight of 0.43 . 10(6) and the following nucleotide composition: 20% cmp, 23.9% amp, 24.2% gmp and 31.9% ump. the accumulation of 14-s rna in chloroplasts of cotyledons of dark-grown plants is stimulated by light. conditions are described for the isolation of 14-s rna in the absence of appreciable fragmentation of chloroplast 23-s rrna and the evidence that it represents a distinct type of chloroplast rna is discussed. translati ... | 1978 | 367438 |
| cell-free transcription and translation of total spinach chloroplast dna. | | 1979 | 374074 |
| fractionation of inducible alkane hydroxylase activity in pseudomonas putida and characterization of hydroxylase-negative plasmid mutations. | the plasmid-determined inducible alkane hydroxylase of pseudomonas putida resolved into particulate and soluble fractions. spinach reductase and spinach ferredoxin could replace the soluble hydroxylase component. two alkane hydroxylase mutants show in vitro complementation (s. benson and j. shapiro, j. bacteriol., 123: 759-760, 1975): one, alk-7, lacks an active soluble component and the other, alk-181, lacks an active particulate component. together with previous results on a particulate alcoho ... | 1977 | 410794 |
| populations of the spinach wilt pathogen, fusarium oxysporum f. sp. spinaciae, in the root tissues, rhizosphere, and soil in the field. | populations of fusarium oxysporum f. sp. spinaciae in root tissues and rhizosphere soil of diseased spinach plants were higher than in the root tissues and rhizosphere soil of healthy plants. populations in soil rhizosphere were higher than in nonrhizosphere soil. the fungus populations were very low in the root tissues of the nonsusceptible strawberry, broccoli, chinese cabbage, and mustard grown in the infested field. the populations were low at the beginning of the season, increased, and rema ... | 1979 | 436018 |
| the synthesis of chloroplast high-molecular-weight ribosomal ribonucleic acid in spinach. | illuminated suspensions of chloroplasts isolated from young spinach leaves show incorporation of [3h]uridine into several species of rna. one such rna species of mr 2.7 x 10(6) shows sequence homology with both the chloroplast 23-s rrna (mr = 1.05 x 10(6)) and 16-s rrna (mr = 0.56 x 10(6)), as judged by dna/rna competition hybridization. leaves labelled in vivo with [32p]orthophosphate in the presence of chloramphenicol accumulate labelled rnas of mr 1.28 x 10(6), 0.71/0.75 x 10(6) and 0.47 x 10 ... | 1979 | 456375 |
| on the control of long-chain-fatty acid synthesis in isolated intact spinach (spinacia oleracea) chloroplasts. | 1. chloroplasts isolated from spinach leaves by using the low-ionic-strength buffers of nakatani & barber [(1977) biochim. biophys. acta.461, 510-512] had higher rates of hco(3) (-)-dependent oxygen evolution (up to 369mumol/h per mg of chlorophyll) and higher rates of [1-(14)c]acetate incorporation into long-chain fatty acids (up to 1500nmol/h per mg of chlorophyll) than chloroplasts isolated by using alternative procedures. 2. acetate appeared to be the preferred substrate for fatty acid synth ... | 1979 | 534525 |
| formation in vivo of volatile n-nitrosamines in man after ingestion of cooked bacon and spinach. | | 1977 | 558518 |
| preparation and characterization of phospholipid-depleted chloroplasts. | spinach class ii chloroplasts were treated with snake venom phospholipase a2 in the presence of bovine serum albumin, and separated by sucrose-density centrifugation. the treatment yielded phospholipid-depleted chloroplasts which had lost 82.6% of the original phospholipids. about 20% of the phospholipids of chloroplasts were resistant to enzyme attack. these results suggest that phospholipids exist in two states in chloroplast membranes. in spite of considerable phospholipid depletion, the chlo ... | 1978 | 638136 |
| isolation of phosphoglycerate kinases by affinity chromatography. | a variety of sepharose derivatives containing dl-o-phosphorylserine or adenosine nucleotides with different points of attachment, has been synthesized and tested for affinity to phosphoglycerate kinase. the most effective gels contained periodate-oxidized atp or adp bound via the ribose by hydrazone formation to adipoyl-dihydrazo-sepharose. the effect of ph, magnesium and buffer ions on the binding capacity of the atp derivative of sepharose has been examined. optimal elution of phosphoglycerate ... | 1978 | 648532 |
| the intake of nitrate, nitrite and volatile n-nitrosamines and the occurrence of volatile n-nitrosamines in human urine and veal calves. | a hundred samples of total diets, 19 samples of cheese (mainly dutch), a total of 30 samples of muscle, fat liver, kidney, blood and fried meat from experimental veal calves (fed daily with 0.6 or 300 mg of potassium nitrate per kg b.w.) and 14 samples of urine of patients medicated with massive amounts of ammonium nitrate (up to an equivalent of 180 mg potassium nitrate per kg b.w.) have been analysed with gc-tea for their content of the following n-nitrosamines: ndma, ndea, ndpa, ndba, npip, n ... | 1978 | 680737 |
| adsorption of bile salts from aqueous solution by plant fibre and cholestyramine. | 1. adsorption of bile salts by dietary fibre is believed to promote their excretion and hence to reduce the serum cholesterol level in man and experimental animals. 2. we have tested a number of plant fibre fractions and other related materials for their ability to adsorb bile salts from aqueous solution. the "insoluble" plant fractions were from "dry grain" (a residue from brewing), apple, wheat bran, lucerne (medicago sativa), soya beans, mung beans (phaseolus mungo), chick peas (cicer arieti ... | 1978 | 698168 |
| inactivation of ribulosebisphosphate carboxylase by modification of arginyl residues with phenylglyoxal. | phenylglyoxal rapidly and completely inactivates spinach and rhodospirillum rubrum ribulosebisphosphate carboxylases. inactivation exhibits pseudo-first-order kinetics and a reaction order of approximately one for both enzymes, suggesting that modification of a single residue per protomeric unit suffices for inactivation. loss of enzymic activity is directly proportional to incorporation of [14c]phenylglyoxal until only 30% of the initial activity remains. for both enzymes, extrapolation of inco ... | 1978 | 728421 |
| low-molecular-weight (4.5s) ribonucleic acid in higher-plant chloroplast ribosomes. | a species of rna that migrates on 10% (w/v) polyacrylamide gels between 5s and 4s rna was detected in spinach chloroplasts. this rna (referred to as 4.5 s rna) was present in amounts equimolar to the 5s rna and its molecular weight was estimated to be approx. 33 000. fractionation of the chloroplast components showed that the 4.5s rna was associated with the 50 s ribosomal subunit and that it could be removed by washing the ribosomes with a buffer containing 0.01 m-edta and 0.5 m-kcl. it did not ... | 1978 | 743229 |
| folate conjugase activity in fresh vegetables and its effect on the determination of free folate content. | the levels of naturally-occurring folate conjugates in fresh asparagus, broccoli, brussels sprouts, cabbage, cauliflower lettuce, and spinach were determined together with the effect on the hydrolysis of pteroylpolyglutamates during the extraction phase of the lactobacillus casei assay. the levels of conjugate activity vary widely among the vegetables tested, from a low of 0.30 +/- 0.21 in lettuce to a high of 106.2 +/- 6.6 mumoles/hr per 100 mg of fresh weight in spinach. the free folate values ... | 1979 | 760505 |
| structure and function of chloroplast-type ferredoxins. | comparison of various chloroplast-type ferredoxin sequences, chemical and enzymic modifications, reconstitution experiments, and fluorescence measurement of chloroplast-type ferredoxins have led to the following conclusions. 1. tyrosine, histidine, and tryptophan residues are not directly involved in the oxidation-reduction mechanism of ferredoxins. the four indispensible cysteine residues in spinach ferredoxin which constitutes a part of the iron-sulfur cluster are located at residues 39, 44. 4 ... | 1976 | 785973 |
| the formation of exchangeable sulphite from adenosine 3'-phosphate 5'-sulphatophosphate in yeast. | a new low-molecular-weight bound sulphite was found in yeast enzyme reaction systems which convert the sulphur of 35s-labelled adenosine 3'-phosphate 5'-sulphatophosphate into exchangeable radioactive sulphite. this bound sulphite was separated from other components by paper electrophoresis and sephadex g-25 chromatography, and shown to be a peptide with multiple thiol groups and an estimated mol.wt. of 1400. the labelled sulphur in this peptide is highly exchangeable with unlabelled sulphite, b ... | 1976 | 791271 |
| flash kinetics and light intensity dependence of oxygen evolution in the blue-green alga anacystis nidulans. | patterns of oxygen evolution in flashing light for the glue-green alga anacystis nidulans are compared with those for broken spinach chloroplasts and whole cells of the green alga chlorella pyrenoidosa. the oscillations of oxygen yield with flash number that occur in both anacystis and chlorella, display a greater degree of damping than do those of isolated spinach chloroplasts. the increase in damping results from a two- to threefold increase in the fraction (alpha) of reaction centers "misse ... | 1975 | 804933 |
| nuclear magnetic resonance studies of the copper binding sites of blue copper proteins: oxidized, reduced, and apoplastocyanin. | proton nuclear resonance spectra at 250 mhz of plastocyanins from spinach (spinacia oleracea) and a blue green alga (anabaena variabilis) are reported. spectra of the reduced plastocyanins contain well-resolved peaks from slowly exchangeable n-h, histidine c2-h tyrosine ring, peptide alpha-ch, and high-field protons. the widths of these peaks indicate that the plastocyanins are monomeric. when the plastocyanins are oxidized, several changes in the spectra are observed including disappearance of ... | 1975 | 809054 |
| possible role of firmly bound atp in the energy transduction of photosynthetic membranes. | chromatophores of rhodospirillum rubrum and spinach chloroplasts contain firmly bound atp that is rapidly labeled along with adp in the presence of 32pi and endogenous nucleotides. the labeling is not entirely dependent on light. in chloroplasts three types of bound atp can be defined methodologically by their extraction properties: buffer-soluble; acid-soluble; and sds-soluble or firmly bound atp. extensive washing of the chloroplasts does reduce buffer-soluble but not acid-soluble and firmly b ... | 1975 | 813067 |
| preparation and properties of immobilized rubredoxin. | rubredoxin, one of the three protein components of the epoxidation/hydroxylation system of pseudomonas oleovorans was immobilized by attachment to cnbr-activated agarose (sepharose 4b). since this represents the first reported example of the preparation of a water-insoluble derivative of an enzyme of this type, the electron transfer and physical properties of the conjugate were examined in order to allow comparison with those of the soluble enzyme. immobilized rubredoxin exhibits all of the majo ... | 1977 | 849934 |
| membranous modifications in sieve element plasids of spinach affected by the aster yellows disease. | | 1977 | 850301 |
| effects of oxalic acid on availability of zinc from spinach leaves and zinc sulfate to rats. | some effects of dietary oxalic acid on availability of zinc from organic and inorganic sources were assessed. male rats fed zinc-deficient diets with and without added sodium oxalate were orally dosed once with either 65zn-labeled spinach leaves or 65zn-labeled zinc sulfate. spinach plants (spinacia oleracea, var. "winter bloomsdale") were grown in 65zn-labeled nutrient solutions that contained 0.033, 0.131 or 0.262 ppm zinc. increasing zinc supply to the plants increased zinc concentration in t ... | 1977 | 864521 |
| the low temperature magnetic circular dichroism spectra of iron-sulphur proteins. ii. two-iron ferredoxins. | variable temperature magnetic circular dichroism (mcd) spectra of a number of two-iron ferredoxins have been measured. the spectra of fully oxidised spinach and spirulina maxima ferredoxin are independent of temperature between room temperature and 18 k, showing that no contribution to the room temperature mcd spectrum arises from the small population of low-lying excited states originating from the exchange coupling. however, the low temperature mcd spectra of the half-reduced proteins spinach ... | 1977 | 880310 |
| solubility properties of fraction i proteins of maize, cotton, spinach, and tobacco. | | 1977 | 881498 |
| glyoxylate aminotransferase in peroxisomes from rat liver and kidney. | an aminotransferase was isolated from peroxisomes that had been separated by isopycnic centrifugation of homogenates from rat liver or kidney. the enzyme was located only in the peroxisomes and in the soluble fraction, presumably from broken peroxisomes. within the peroxisomes, this aminotransferase was in the soluble matrix. this specific aminotransferase was not found in spinach leaves. the enzyme was relatively specific for glyoxylate as the amino group acceptor. l-leucine and l-phenylalanine ... | 1976 | 932037 |
| purification and properties of a four iron-four sulfur protein from a pseudomonas species. | we have isolated an iron-sulfur proteins from a pseudomonas species grown on glucose. this protein has different properties from the two known iron-sulfur proteins isolated from other pseudomonas species: rubredoxin and putidaredoxin. the iron-sulfur protein was purified to homogeneity by deae-cellulose column chromatography and sephadex g-75 gel filtration. the absorption spectrum of the oxidized iron-sulfur protein shows a peak at 283 nm with shoulders at about 290, 320, and 410 nm. the protei ... | 1976 | 956144 |
| size, conformation and purity of chloroplast dna of some higher plants. | 1. chloroplast dna of antirrhinum majus, oenothera hookeri, beta vulgaris and spinacia oleracea band at the same buoyant density of 1.697 g-cm-3 in neutral cscl equilibrium gradients. the corresponding nuclear dnas band at 1.691, 1.703, 1.695 and 1.695 g-cm-3, respectively. the purity of chloroplast and nuclear dna can be assessed objectively only in the cases of antirrhinum and oenothera. 2. electron microscopic analysis of chloroplast dna, purified in cscl or cscl/ethidium bromide gradients, r ... | 1975 | 1092350 |
| polypeptide nature of growth requirement in yeast extract for thermoplasma acidophilum. | the active component(s) in yeast extract required by thermoplasma acidophilum for growth is polypeptide in nature. a fraction from yeast extract was isolated and partially characterized as one or more peptides of molecular weight about 1,000 containing 8 to 10 amino acids. although it was composed largely of basic and dicarboxylic amino acids, only one amino group per molecule was free. the polypeptide(s) appeared to bind avidly to cations. no other organic compounds except glucose were needed b ... | 1975 | 1102535 |
| [reciprocal action of various substances contained in spinach on suckling pigs]. | | 1975 | 1136601 |
| the molecular size and conformation of the chloroplast dna from higher plants. | covalently closed circular choloroplast dna (ctdna) molecules have been isolated from pea, bean, spinach, lettuce, corn and oat plants by ethidium bromide/cesium choloride density-gradient entrifugation. as much as 30-40% of the total ctdna could be isolated as closed circular dna molecules and up to 80% of the total ctdna was found in the form of circular molecules. the size of pea, spinach, lettuce, corn and oat ctdna relative to an internal standard (phix174 replicative form ii monomer dna) w ... | 1975 | 1164522 |
| 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 electron transport to nitrogenase in mycobacterium flavum. | 1. two ferredoxin-type iron-sulfur proteins have been isolated from mycobacterium flavum 301 grown under nitrogen-fixing, iron-sufficient conditions. no flavodoxin was observed. 2. these ferredoxins are apparently soluble: they were present in the supernatant fraction after disrupting by decompression. only small amounts were present in particulate fractions. 3. the two ferredoxins were separated by chromatography on deae-cellulose, sephadex or electrophoresis. 4. both ferredoxins mediated the t ... | 1976 | 1252086 |
| chemical reactivity of labile sulfur of iron-sulfur proteins. the reaction of triphenyl phosphine. | the reaction of triphenyl phosphine to iron-sulfur proteins from adrenal cortex mitochondria, spinach chloroplasts, and clostridium pasteurianum was investigated. as ethanol concentrations in the reaction mixture increased, the rate of the reaction decreased. in the simultaneous presence of 1 m kc1 and 5 m urea, the reaction rate reached at maximum. under these conditions the initial rates of the decolorization reaction by the phosphine were found to be 8.7, 0.88, and 1.8 nmol of ferredoxin per ... | 1976 | 1276162 |
| resonance raman studies of rieske-type proteins. | resonance raman (rr) spectra are reported for the [2fe-2s] rieske protein from thermus thermophilus (trp) and phthalate dioxygenase from pseudomonas cepacia (pdo) as a function of ph and excitation wavelength. depolarization ratio measurements are presented for the rr spectra of spinach ferredoxin (sfd), trp, and pdo at 74 k. by comparison with previously published rr spectra of sfd, we suggest reasonable assignments for the spectra of trp and pdo. the spectra of pdo exhibit virtually no ph depe ... | 1992 | 1280165 |
| [the correlation between the maturation of rbcl transcripts and its flanking sequence in a prokaryotic system]. | there is a 15bp large reverse repeated sequence proceeded by a 7bp small one in the 3'flanking region of rbcl of nicotiana tabacum. a 383 bp of xbai fragment containing these tandemly repeats was inserted into the plasmid p lambda s delta, at the position between the lambda p and the cat gene. then these two repeats were separated and deleted systematically to obtain various deletions. the deletion prt65, prt74 and prt83 was sequenced to determine the deleted base pairs exactly. s1 mapping analy ... | 1992 | 1305827 |
| ca(2+)-dependent ubiquitination of calmodulin in yeast. | recently we were able to show that calmodulin from vertebrates, plants (spinach) and the mold neurospora crassa can be covalently conjugated to ubiquitin in a ca(2+)-dependent manner by ubiquityl-calmodulin synthetase (ucam-synthetase) from mammalian sources [r. ziegenhagen and h.p. jennissen (1990) febs lett. 273, 253-256]. it was therefore of high interest to investigate whether this covalent modification of calmodulin also occurs in one of the simplest eukaryotes, the unicellular saccharomyce ... | 1992 | 1309706 |
| plant mitochondrial f0f1 atp synthase. identification of the individual subunits and properties of the purified spinach leaf mitochondrial atp synthase. | spinach leaf mitochondrial f0f1 atpase has been purified and is shown to consist of twelve polypeptides. five of the polypeptides constitute the f1 part of the enzyme. the remaining polypeptides, with molecular masses of 28 kda, 23 kda, 18.5 kda, 15 kda, 10.5 kda, 9.5 kda and 8.5 kda, belong to the f0 part of the enzyme. this is the first report concerning identification of the subunits of the plant mitochondrial f0. the identification of the components is achieved on the basis of the n-terminal ... | 1992 | 1313368 |
| effect of coprophagy on bioavailability of iron from plant foods fed to anemic rats. | effects of coprophagy and coprophagy preventing device on iron bioavailability were evaluated in two experiments. in experiment 1, rats were fed diets with feso4, spinach, bran cereal or cornmeal as the iron source. the rats in each diet group were fitted with collars, sham-collars or not fitted with collars (control). in experiment 2, rats were fed diets with feso4 or green peas as the iron source and were fitted with collars, tail cups, sham-collars or not fitted with any device (control). pre ... | 1992 | 1315435 |
| the amino acid sequence of nucleoside diphosphate kinase i from spinach leaves, as deduced from the cdna sequence. | the primary structure of nucleoside diphosphate (ndp) kinase from spinach leaves has been deduced from its cdna sequence. a lambda gt 11 cdna library derived from spinach leaves was screened using an antibody against ndp kinase i, which we previously purified to electrophoretic homogeneity (t. nomura, t. fukui, and a. ichikawa, 1991, biochim. biophys. acta 1077, 47-55). the cdna sequences of positive clones contained the amino acid coding region (444 base pairs) for ndp kinase i as well as 5' an ... | 1992 | 1322113 |
| direct expression of active spinach glycolate oxidase in escherichia coli. | spinach glycolate oxidase (gao) was expressed in escherichia coli using the t7 rna polymerase promotor. the enzyme accounts for approx. 1% of the soluble protein fraction and is expressed as a soluble and active enzyme. comparison with gao expressed in saccharomyces cerevisiae (macheroux, p., massey, v., thiele, d.j. and volokita, m. (1991) biochemistry 30, 4612-4619) showed that the gao expressed in e. coli has identical physico-chemical features to the wild-type enzyme, but is expressed at a l ... | 1992 | 1324737 |
| comparison of structure of quinone redox site in the mitochondrial cytochrome-bc1 complex and photosystem ii (qb site). | a series of nitrophenolic electron-transport inhibitors (2-substituted 4,6-dinitrophenols) of rat liver mitochondrial cytochrome-bc1 complex and of photosystem ii (qb site) of spinach thylakoids was synthesized. the structure/inhibitory-activity relationship was examined to elucidate differences in the three-dimensional structure of the quinone redox site in the two systems. these inhibitors occupy the ubiquinone redox site of cytochrome-bc1 complex competitively with natural ubiquinol, probably ... | 1992 | 1327783 |
| purification and characterization of 3-ketoacyl-acyl carrier protein synthase iii from spinach. a condensing enzyme utilizing acetyl-coenzyme a to initiate fatty acid synthesis. | the 3-ketoacyl-acyl carrier protein (acp) synthase iii from spinach was purified to homogeneity by an eight-step procedure that included an acp-affinity column. the size of the native enzyme was m(r) = 63,000 based on gel filtration, and its subunit size was m(r) = 40,500 based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting that 3-ketoacyl-acp synthase iii may be a homodimer. the purified enzyme was highly specific for acetyl-coa and malonyl-acp. the km for acetyl-coa w ... | 1992 | 1328217 |
| protein-tyrosyl radical interactions in photosystem ii studied by electron spin resonance and electron nuclear double resonance spectroscopy: comparison with ribonucleotide reductase and in vitro tyrosine. | the stable tyrosine radical in photosystem ii, yd*, has been studied by esr and endor spectroscopies to obtain proton hyperfine coupling constants from which the electron spin density distribution can be deduced. simulations of six previously published esr spectra of psii (one at q band; five at x band, of which two were after specific deuteration and two others were of oriented membranes) can be achieved by using a single set of magnetic parameters that includes anisotropic proton hyperfine ten ... | 1992 | 1332777 |
| sequence of a cdna encoding nitrite reductase from the tree betula pendula and identification of conserved protein regions. | the sequence of an mrna encoding nitrite reductase (nir, ec 1.7.7.1.) from the tree betula pendula was determined. a cdna library constructed from leaf poly(a)+ mrna was screened with an oligonucleotide probe deduced from nir sequences from spinach and maize. a 2.5 kb cdna was isolated that hybridized to an mrna, the steady-state level of which increased markedly upon induction with nitrate. the nucleotide sequence of the cdna contains a reading frame encoding a protein of 583 amino acids that r ... | 1992 | 1347145 |
| characterization of plastid 5-aminolevulinate dehydratase (alad; ec 4.2.1.24) from spinach (spinacia oleracea l.) by sequencing and comparison with non-plant alad enzymes. | we have sequenced 5-aminolevulinate dehydratase (alad; ec 2.4.1.24) of a plant. a full-length cdna clone (1727 bp) encoding this enzyme has been identified by immunoscreening a lambda gt 11 cdna library of spinach. alad is not a plant-specific enzyme; however, the plant enzyme differs from the well known alad enzymes of bacteria, yeast and animals in structural and biochemical properties and in that it is located in the plastid. differences and homologies can be traced back to the molecular leve ... | 1992 | 1351729 |
| identification, characterization, and dna sequence of a functional "double" groes-like chaperonin from chloroplasts of higher plants. | chloroplasts of higher plants contain a nuclear-encoded protein that is a functional homolog of the escherichia coli chaperonin 10 (cpn10; also known as groes). in pea (pisum sativum), chloroplast cpn10 was identified by its ability to (i) assist bacterial chaperonin 60 (cpn60; also known as groel) in the atp-dependent refolding of chemically denatured ribulose-1,5-bisphosphate carboxylase and (ii) form a stable complex with bacterial cpn60 in the presence of mg.atp. the subunit size of the pea ... | 1992 | 1356267 |
| the single-copy gene psbs codes for a phylogenetically intriguing 22 kda polypeptide of photosystem ii. | recombinant phages that encode the complete precursor polypeptide for the 22 kda polypeptide associated with photosystem ii have been serologically selected from two lambda gt11 expression libraries made from polyadenylated rna of spinach seedlings. the cdnas hybridize to a 1.3 kb rna species. the precursor protein is comprised of 274 amino acid residues and carries an n-terminal transit peptide of probably 69 amino acid residues. the mature protein exhibits four predicted transmembrane segments ... | 1992 | 1360412 |
| isolation and partial amino acid sequence of domains of nitrate reductase from spinach. | fragments of spinach nitrate reductase (nr) were prepared by limited proteolysis of immunopurified enzyme using both staphylococcus aureus v8 protease and trypsin. incubation of nr with v8 protease yielded two enzymically active fragments which could be size separated by fplc on a superose 12 column or subjected to further proteolysis while bound to a blue sepharose affinity column. an nadh-ferricyanide (nadh-fr) active fragment bound to, and was eluted from, a blue sepharose column by micromola ... | 1991 | 1367837 |
| isolation and characterization of a cdna from cuphea lanceolata encoding a beta-ketoacyl-acp reductase. | a cdna encoding beta-ketoacyl-acp reductase (ec 1.1.1.100), an integral part of the fatty acid synthase type ii, was cloned from cuphea lanceolata. this cdna of 1276 bp codes for a polypeptide of 320 amino acids with 63 n-terminal residues presumably representing a transit peptide and 257 residues corresponding to the mature protein of 27 kda. the encoded protein shows strong homology with the amino-terminal sequence and two tryptic peptides from avocado mesocarp beta-ketoacyl-acp reductase, and ... | 1992 | 1376402 |
| import and processing of the precursor of the rieske fes protein of tobacco chloroplasts. | cdna clones encoding the precursor of the rieske fes protein of tobacco chloroplasts have been characterised and shown to derive from two different genes. the 5' ends of the corresponding transcripts have been cloned using primer extension and pcr. the nucleotide sequences of the cdnas (and their 5' extensions) predict precursors for the tobacco proteins which differ in 4 amino acid residues out of a total of 228 residues and show high homology with the pea and spinach precursors. the tobacco pr ... | 1992 | 1391772 |
| biosynthesis of active spinach-chloroplast thioredoxin f in transformed e. coli. | the recently cloned gene for spinach chloroplast thioredoxin f was subcloned in a modified pkk233-2 expression vector and used for transformation of escherichia coli cells containing the iq plasmid. after induction with iptg (isopropyl-beta-d-thiogalactoside) the transformed cells produce the chloroplast protein in large amounts as insoluble deposit within the cell. the protein has been solubilized, purified and analysed for activity. it shows no difference in catalytic activity from native spin ... | 1992 | 1391773 |
| a novel light-regulated promoter is conserved in cereal and dicot chloroplasts. | the chloroplast psbd-psbc genes encode d2 and cp43, a reaction center protein and chlorophyll-binding antenna protein of photosystem ii, respectively. we have previously shown that differential accumulation of light-induced psbd-psbc mrnas in barley chloroplasts is due to transcription from a blue light-responsive promoter (lrp). it is hypothesized that the light-induced mrnas help to maintain levels of the d2 polypeptide, which is photodamaged and degraded in illuminated plants. to determine if ... | 1992 | 1392595 |
| molecular cloning of a cdna clone for tobacco lipid transfer protein and expression of the functional protein in escherichia coli. | a cdna clone encoding a lipid transfer protein (ltp) was isolated from tobacco by screening a library with a pcr-amplified spinach ltp gene. dna sequence analysis showed a large open reading frame (344 bp) encoding a polypeptide of 114 amino acids. the first 23 amino acids of the deduced protein have the characteristics of a signal peptide for protein secretion or targeting into dense microbody-like vesicles. the cdna clone was then inserted into an expression vector, pmal, and expressed in e. c ... | 1992 | 1397298 |
| purification and initial characterization of the proteasome from the higher plant spinacia oleracea. | the proteasome (multicatalytic protease complex), a high molecular weight protein complex, has been purified from spinach leaves by successive chromatography on deae-cellulose, bio-gel a-1.5m, deae-toyopearl 650c, and deae-5pw. the molecular mass was estimated to be 850 kda by gel filtration. polyacrylamide gel electrophoresis of the proteasome gave a single protein band under nondenaturing conditions and at least 10 bands in the range of 21-32 kda in the presence of sodium dodecyl sulfate. by e ... | 1992 | 1400479 |
| nuclear-encoded tobacco chloroplast ribosomal protein l24. protein identification, sequence analysis of cdnas encoding its cytoplasmic precursor, and mrna and genomic dna analysis. | using a nicotiana tabacum leaf cdna library in the expression vector lambda gt11, two cdnas encoding the full-length precursor polypeptide (m(r) 20,696) of tobacco chloroplast ribosomal protein l24 were identified and sequenced. these cdnas encode a mature protein of 146 amino acids (m(r) 16,418) with a transit peptide of 41 amino acids (m(r) 4,278). the mature tobacco l24 protein has 78, 65, 45, and 35% sequence identity with ribosomal proteins l24 of pea, spinach, bacillus subtilis, and escher ... | 1992 | 1400480 |
| comparison of sulfoquinovosyl diacylglycerol from spinach and the purple bacterium rhodobacter spaeroides by fast atom bombardment tandem mass spectrometry. | isolated sulfoquinovosyl-diacylglycerol (sqd) from spinach and the purple bacterium rhodobacter sphaeroides provide two sources of very different molecular species of sqd. we were able to demonstrate by fast atom bombardment-collisionally activated dissociation tandem mass spectrometry in the negative ion mode that the sulfoquinovosyl head group of the plant and bacterial lipids can be characterized by the common fragmentation pattern found in the spectra of both samples. differences in the acyl ... | 1992 | 1406075 |
| multiple plant rna binding proteins identified by pcr: expression of cdnas encoding rna binding proteins targeted to chloroplasts in nicotiana plumbaginifolia. | pre-mrna processing in eukaryotic cells requires the participation of multiple protein factors and ribonucleoprotein particles. one class of proteins involved in this process are rna-binding proteins, which contain a domain of ca. 90 amino acids with a characteristic ribonucleoprotein consensus sequence (rnp-cs). a pcr approach that is suitable for the characterization of rnp-cs-type proteins is described. fifteen different rna-binding domains were amplified from nicotiana tabacum (tobacco) usin ... | 1992 | 1406585 |
| subunit interactions of rubisco activase: polyethylene glycol promotes self-association, stimulates atpase and activation activities, and enhances interactions with rubisco. | the effect of polyethylene glycol (peg) on the enzymatic and physical properties of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) activase was examined. in the presence of peg, rubisco activase exhibited higher atpase and rubisco activating activities, concomitant with increased apparent affinity for atp and rubisco. specific atpase activity, which was dependent on rubisco activase concentration, was also higher in the presence of ficoll, polyvinylpyrrolidone, and bovine serum albumi ... | 1992 | 1416997 |
| role of the carboxy terminus of polypeptide d1 in the assembly of a functional water-oxidizing manganese cluster in photosystem ii of the cyanobacterium synechocystis sp. pcc 6803: assembly requires a free carboxyl group at c-terminal position 344. | the d1 polypeptide of the photosystem ii (psii) reaction center is synthesized as a precursor polypeptide which is posttranslationally processed at the carboxy terminus. it has been shown in spinach that such processing removes nine amino acids, leaving ala344 as the c-terminal residue [takahashi, m., shiraishi, t., & asada, k. (1988) febs lett. 240, 6-8; takahashi, y., nakane, h., kojima, h., & satoh, k. (1990) plant cell physiol. 31, 273-280]. we show here that processing on the carboxy side o ... | 1992 | 1420199 |
| purification and characterization of seven chloroplast ribosomal proteins: evidence that organelle ribosomal protein genes are functional and that nh2-terminal processing occurs via multiple pathways in chloroplasts. | putative genes for 21 ribosomal proteins (rps) have been identified in the chloroplast dna of four plants by nucleotide sequencing and homology comparison but few of the gene products have been characterized. here we report the purification and n-terminal sequencing of seven proteins from the spinach chloroplast ribosome. the data show them to be the homologues of escherichia coli rps l20, l32, l33, l36, s12, s16 and s19, and thus support the view that their genes identified in the chloroplast d ... | 1992 | 1421149 |
| studies on the holoenzyme biogenesis of the spinach ferredoxin-nadp+ reductase. | an expression plasmid, pprefnr, in which the dna sequence coding for the spinach ferredoxin-nadp+ reductase precursor was under the control of prokaryotic transcription and translation initiation signals has been constructed. the plasmid directed the synthesis in escherichia coli of a 43-kda immunoreactive polypeptide which could be identified with the reductase preprotein. analyses of bacterial extracts showed that the precursor was unstable and devoid of catalytic activities, suggesting that t ... | 1992 | 1444474 |
| a laser flash absorption spectroscopy study of anabaena sp. pcc 7119 flavodoxin photoreduction by photosystem i particles from spinach. | electron transfer from p700 in photosystem i (psi) particles from spinach to anabaena sp. pcc 7119 flavodoxin has been studied using laser flash absorption spectroscopy. a non-linear protein concentration dependence of the rate constants was obtained, suggesting a two-step mechanism involving complex formation (k = 3.6 x 10(7) m-1.s-1) followed by intracomplex electron transfer (k = 270 s-1). the observed rate constants had a biphasic dependence on the concentrations of nacl or mgcl2, with maxim ... | 1992 | 1446742 |
| expression of subunit ii of chloroplast h(+)-atpase in an escherichia coli mutant lacking subunit b of its h(+)-atpase. | the dna of subunit ii of the h(+)-atpase from spinach chloroplast was expressed in escherichia coli. it was found that a high gene dose is lethal to e. coli. with a lower gene dose subunit ii was not able to substitute for the homologous subunit b in the e. coli atp synthase. | 1992 | 1449071 |