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Whole bean (var. "Eastern Butterwax") plants and isolated cells were used to investigate possible mechanisms of action of glyphosate [N-(phosphonomethyl)glycine]. Results showed that glyphosate was quickly absorbed by the whole plant but not by individual cells and that it caused a rapid reduction in leaf dry matter ac... |
Vacuoles were isolated from protoplasts of Nicotiana glutinosa by the method of Mettler and Leonard (Plant Physiol 1979 64: 1114-1120) with minor modifications so that the number of intact protoplasts contaminating the vacuole preparation was reduced to less than 1% (by number). Isopycnic centrifugation of a [(3)H]chol... |
Previous data in the literature have indicated that phytochrome could alter the rate of reduction of exogenously added NADP by a pea mitochondrial preparation in vitro. These results could not be duplicated using a mitochondrial preparation isolated from etiolated oat seedlings. Further experimentation demonstrated tha... |
Two forms of alpha-galactosidase (alpha-d-galactoside galactohydrolase, E.C. 3.2.1.22) which differed in molecular weight were resolved from Cucumis sativus L. leaves. The enzymes were partially purified using ammonium sulfate fractionation, Sephadex gel filtration, and diethylaminoethyl-Sephadex chromatography. The mo... |
Selenocysteine, the selenium analog of cysteine, was identified in proteins of Vigna radiata (L.) Wilczak grown with selenate. To stabilize selenocysteine and prevent its breakdown, the carboxymethyl derivative was synthesized by the addition of iodoacetic acid to the protein extract from [(75)Se]selenate-grown plants.... |
The main focus of this study was to determine the mechanism by which certain exogenous monovalent salts stimulate rates of net O(2) evolution linked to oxaloacetate reduction in intact spinach chloroplasts. The influence of salts on the dicarboxylate translocator involved in the transport of oxaloacetate and on the act... |
In the seedcoats of developing pea seeds, the maximal activities of asparaginase (EC 3.5.1.1) and aspartate: alpha-ketoglutarate aminotransferase (EC 2.6.1.1) are attained early in development, before the embryo has expanded to fill the embryo sac. These two enzyme activities could account for the early absence of aspa... |
Mixed micelles of (32)P-labeled phosphatidylcholine or phosphatidic acid (PA) and the nonionic detergent octylphenol polyethylene oxide (NP-40 Nonidet) were used to assay the activities of phospholipase D and PA phosphatase in crude extracts of mung bean (Vigna radiata) cotyledons. Together these enzymes degrade phosph... |
Transfer RNA from wheat germ, yeast, and Escherichia coli inhibited the indoleacetic acid (IAA)-induced spectral change in horseradish peroxidase (EC 1.11.1.7) and the decarboxylation of IAA. The inhibition was limited to a delay after which the increase in A(427) and the decarboxylation of IAA resumed at the same rate... |
The salt-extractable hydroxyproline-rich glycoprotein (HRGP) of the cell wall of aerated carrot root discs has been studied by polyacrylamide gel electrophoresis. The predominant proline-labeled protein extractable from the cell wall is rich in hydroxyproline as shown by its specific loss of (3)H from proline labeled i... |
A method is described to achieve density labeling of proteins in unicellular algae by using (13)CO(2). This is a satisfactory procedure especially for work on nitrogen metabolism. The increase in activity of glutamine synthetase (EC 6.3.1.2.) and glutamate synthase (EC 1.4.7.1.) in Chlorella sorokiniana mediated by a d... |
Dark activation of light-inactivated glucose-6-phosphate dehydrogenase was inhibited by catalase in a broken pea chloroplast system. Partially purified glucose-6-phosphate dehydrogenase from pea leaf chloroplasts can be inactivated in vitro by dithiothreitol and thioredoxin and reactivated by H(2)O(2). The in vitro act... |
The major storage protein fraction, globulin-1 protein, of French bean (Phaseolus vulgaris L.) was analyzed by two-dimensional electrophoresis. The protein pattern suggested a more complex system for globulin-1 protein than the model of three polypeptides, alpha, beta, and gamma, differing in molecular weight. Isoelect... |
A new bacterial agglutinin was isolated from seeds of the soybean cultivar Clark. Purification was carried out by ammonium sulfate precipitation and ion-exchange chromatography. The agglutinin is a heat-labile glycoprotein most active at pH 4.0. Addition of Ca(2+), Mn(2+) and Mg(2+) did not enhance the agglutinating ac... |
The chloroplastic and the cytoplasmic phosphorylases were purified and their kinetic properties characterized. The cytoplasmic enzyme was purified to homogeneity via affinity chromatography on a glycogen-Sepharose column. Subunit molecular weight studies indicated a value of 92,000, whereas a native molecular weight va... |
The properties of two amylase activities which differ in their substrate specificity and subcellular location as well as a chloroplast-associated R-enzyme (debranching activity) are reported. An extrachloroplastic amylase is resolved by gel filtration chromatography into two activities of 80,000 and 40,000 daltons. Bot... |
The effect of nitrogen and sulfur nutrition on sulfate permease and O-acetylserine sulfhydrylase was studied in tobacco cells.Sulfate transport rates increased 10-fold in cells transferred to sulfur-deficient B-5 medium. The addition of either sulfate or l-cysteine reduced transport 95 and 80%, respectively. The pools ... |
Binding of [(3)H]gibberellin A(1) (GA(1)) to extracts of dwarf pea epicotyls was investigated using sliced pea epicotyls (0.5-1.0 millimeter thick) that had been incubated in a solution containing [(3)H]GA(1) at 0 C for 3 days. Gel filtration of a 100,000g supernatant indicated binding to a high (HMW) and an intermedia... |
Phosphofructokinase (EC 2.7.1.11) from carrot roots was activated by a number of salts. Increase in salt concentration beyond the optimum generally led to a decrease in enzyme activity. Salts of the multivalent anions sulfate and phosphate were very effective activators and inhibitors. Potassium acetate and potassium s... |
A major protease present in dormant bark tissues of the apple (Malus domestica Borkh. cv. "Golden Delicious") was partially purified by hemoglobin-coupled Sepharose column chromatography. The protease active at pH 4.6 and at temperatures of 30 to 50 C was found to be sulfhydryl-dependent. Phenylmercuric acetate inhibit... |
The polypeptide complement of enriched soybean (Glycine max [L.] Merr. cult. wells) root plasma membrane fractions was studied by two-dimensional gel electrophoresis. Good resolution was obtained when polypeptides were solubilized in sodium dodecyl sulfate and when butylated hydroxytoluene was included in the vesicle i... |
Simple methods are described for following in vivo the rate of peptidylproline hydroxylation and for determining what proportion of the total proline incorporated into protein is hydroxylated. |
The intracellular binding of dinitroaniline herbicides was studied in order to analyze the mechanism of their colchicine-like action. When corn root apices (5 millimeters) are incubated in [(14)C]oryzalin (a dinitroaniline herbicide), the (14)C is taken up rapidly, reaching a plateau in about 4 hours, which corresponds... |
Conditions for obtaining reproducible light-induced reduction of a b-type cytochrome in membrane fractions from coleoptiles of dark-grown Zea mays L. include a glucose-glucose oxidase system that lowers O(2) tension and generates H(2)O(2), substrate amounts of ethylenediaminetetraacetic acid which, in some manner, faci... |
A receptor protein for the auxin transport inhibitor, N-1-naphthylphthalamic acid (NPA), has been solubilized from corn coleoptile membranes using Triton X-100. [(3)H]NPA binding activity of the receptor was compared in soluble and membrane-bound states. Both activities are abolished by treatment with trypsin. Differen... |
S-Adenosylmethionine decarboxylase (EC 4.1.1.50) has been purified 500-fold in 30% yield from the extract of etiolated corn seedlings (cv. Golden Crossbantam Bell). This preparation had a molecular weight of approximately 25,000. The K(m) value was 5 micromolar for S-adenosylmethionine. Methylglyoxal bis(guanylhydrazon... |
A survey of the K(m)(CO(2)) values of ribulose-1,5-bisphosphate carboxylase from 60 grass species shows that enzyme from C(3) grasses consistently exhibits lower K(m)(CO(2)) than does that from C(4) grasses. Systematically ordered variation in K(m)(CO(2)) of ribulose-1,5-bisphosphate carboxylases from C(3) and C(4) gra... |
Transfer of Lemna minor fronds to adverse or stress conditions produces a large increase in the rate of protein degradation. Cycloheximide partially inhibits stress-induced protein degradation and also partially inhibits the protein degradation which occurs in the absence of stress. The increased protein degradation do... |
Leaf senescence in field-grown soybean (Merrill) as defined by the period after full expansion, was studied by measuring abscisic acid (ABA), total soluble protein, and chlorophyll in leaves through the later part of the growing season. ABA concentrations increased significantly at the end of the season when leaves had... |
A 3-phosphoglycerate phosphatase activity of about 2 micromoles per minute per milligram chlorophyll is associated with the thylakoid membranes of spinach chloroplasts. The K(m) for 3-phosphoglycerate is 3 millimolar. The enzyme can be solubilized from thylakoid membranes by treatment with 0.33 molar MgCl(2) or sodium ... |
Three proteinases which digest hemoglobin rapidly at acid pH (3.5 to 4.5) were identified in crude extracts of soybean (Merr.) leaves and separated by chromatography on DEAE-cellulose. All three enzymes were endopeptidases as judged by the ratio of alpha-amino-nitrogen plus peptide nitrogen over alpha-amino-nitrogen in... |
Two methods of measuring protein breakdown resulting from self-digestion during incubation in extracts of soybean leaves were examined. The release of free alpha-amino-nitrogen was measured with ninhydrin, and the disappearance of the large subunit of ribulose bisphosphate carboxylase (RuBPcase) was followed with sodiu... |
A new procedure is reported for high-yield isolation of guard cell protoplasts from Vicia faba L. Delayed light emission and P(700) content plus absorption and fluorescence emission spectra of these protoplast extracts are reported. It is concluded that both photosystems are present. The presence of photosystem II and ... |
An antibody for phosphoenolpyruvate carboxylase was used to isolate and to quantitate the enzyme from greening maize (cv. KOU 6) leaves. The increase in enzyme activity during greening was due to de novo synthesis, which was paralleled by increases in enzyme protein and incorporation of leucine. The light-induced activ... |
Aldose-6-phosphate reductase (alditol 6-phosphate:NADP 1-oxidoreductase) was isolated and characterized from mature apple leaves (Malus domestica cv. Starkrimson). The enzyme was purified 79-fold. The enzyme catalyzed the following reversible reaction: d-glucose 6-phosphate + NADPH + H(+) right arrow over left arrow d-... |
A protein which binds 6-substituted purines of the cytokinin type with relatively high affinity has been extensively purified from wheat germ. Conventional chromatographic techniques, as well as an affinity matrix to which a cytokinin was covalently coupled, were used in the purification. The wheat germ cytokinin-bindi... |
A phosphatase has been partially purified from crude extracts of Poterioochromonas malhamensis. The enzyme appears to be specific for alpha-galactosyl-(1 --> 1)-glycerol 3-phosphate as it is relatively inactive towards glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, and sn-glycerol 3-phosphate. |
During light-induced greening of dark-grown, nondividing Euglena gracilis Z, there is a delay of about 10 hours in the formation of active photosystem II (PSII) reaction centers compared to chlorophyll synthesis. Experiments with greening under different light intensities rule out the possibility that this delay result... |
Greening cells of Euglena were transferred back to darkness at different stages of chloroplast development in the presence or absence of specific inhibitors of protein synthesis. The analysis of chloroplast components showed that: (a) cycloheximide or streptomycin does not significantly inhibit the formation in darknes... |
The (K(+),Mg(2+))-ATPase was partially purified from a plasma membrane fraction from corn roots (WF9 x Mol7) and stored in liquid N(2) without loss of activity. Specific activity was increased 4-fold over that of the plasma membrane fraction. ATPase activity resembled that of the plasma membrane fraction with certain a... |
A marked increase in beta-acetylglucosaminidase (2-acetamido-2-deoxy-beta-d-glucoside acetamidodeoxyglucohydrolase, EC 3.2.1.30) activity was observed in the germinating cotyledon of cotton seeds. The enzyme was isolated from cotton seedlings and purified to study its physiological function in the germination of cotton... |
When mannose was included in the enzyme incubation medium during the preparation of protoplasts from leaves of spinach, maltose was an early product of protoplast photosynthesis and, after 12 minutes, accounted for up to 15% of the (14)C incorporated from (14)CO(2). Maltose was not detected in protoplasts prepared in t... |
Lipoxygenase was demonstrated in young cotton seedlings. It catalyzed the oxygenation of linoleic or linolenic acid, predominantly at carbon 13, and its molecular weight was estimated by gel filtration to be 100,000. Hydroperoxide isomerase was also present and converted hydroperoxylinoleic or hydroperoxylinolenic acid... |
Polyribosomal RNA isolated from pea cotyledons at various developmental stages programmed the cell-free synthesis of polypeptides which were recognized by antibodies specific for pea storage proteins. There were quantitative and qualitative changes in the template activity during seed maturation. Most of the polysomal ... |
To study the role of sorbitol-6-phosphate dehydrogenase in sorbitol synthesis in leaves of Rosaceous plants, properties of the enzyme and its presence in several plants in the family was investigated. The activity of the enzyme, which catalyzes an NADP-dependent oxidation of the substrate to glucose-6-phosphate, was de... |
A sensitive assay procedure is described for the simultaneous determination of ribulose-1,5-bisphosphate (RuBP) carboxylase and oxygenase activities. In this assay, [1-(3)H]RuBP is incubated with (14)CO(2) and O(2). Carboxylation rate is determined from (14)CO(2) incorporation and oxygenation rate is determined from [2... |
CDPcholine:1,2-diacylglycerol cholinephosphotransferase (EC 2.7.8.2) and CDPethanolamine:1,2-diacylglycerol ethanolaminephosphotransferase (EC 2.7.8.1) were detected in mitochondrial fractions from castor bean (Ricinus communis) endosperm. These activities were not due to contamination of the fractions with endoplasmic... |
The specific activity of arginine decarboxylase (ADC; l-arginine carboxylase; EC 4.1.1.19) rises steadily over an 8 hour experimental period in the growing buds and subapical epicotyl internodes of 6-day-old totally etiolated pea seedlings. Treatment with red light (R) completely annuls this rise in epicotyls but incre... |
A recognition molecule was isolated from stigmas of S-allele genotype S(2)S(2) of Brassica oleracea var. capitata L. After Sephadex chromatography, it eluted as a single symmetrical peak during diethylaminoethane-cellulose chromatography. A high degree of purity was affirmed by: sedimentation as a single peak during ul... |
l-Methionyl-tRNA synthetase (EC 6.1.1.10) from seeds of Phaseolus aureus has been purified approximately 290-fold. Optimum assay conditions were determined by using the ATP-pyrophosphate exchange assay and the aminoacylation assay. The enzyme catalyzes both selenomethionine- and selenoethionine-dependent ATP-pyrophosph... |
ATP sulfurylase (EC 2.7.7.4), cysteinyl-tRNA synthetase (EC 6.1.1.16), and methionyl-tRNA synthetase (EC 6.1.1.10) from Neptunia amplexicaulis have been purified approximately 162-, 140- and 185-fold, respectively. Purified ATP sulfurylase in the presence of purified inorganic pyrophosphatase catalyzed the incorporatio... |
Various properties of phosphoenolpyruvate carboxylases were compared in leaf preparations from C(3)-C(4) intermediate, C(3), and C(4)Panicum species. Values of V(max) in micromoles per milligram chlorophyll per hour at pH 8.3 were 57 to 75 for the enzyme from Panicum milioides, Panicum schenckii, and Panicum decipiens ... |
Microbodies were isolated by zonal-rotor sucrose density gradient centrifugation from cotton (cv. DP 61) seeds at two distinct stages of embryogenesis (38 and 50 days after anthesis) and after 48 hours postgerminative growth. In all cases, beta-oxidation activity (palmitoyl-coenzyme A (CoA)-dependent reduction of acety... |
Dark-induced senescence in leaf discs from O(3)-sensitive red clover trifoliates (Trifolium pratense L. cv. ;Pennscott') was markedly retarded by treatment with N-[2-(2-oxo-1-imidazolidinyl)ethyl-N'-phenylurea (EDU). EDU also protects against acute and chronic foliar O(3) injury when sprayed on intact leaves or supplie... |
Factors with potential for regulating pyrimidine biosynthesis in plant tissue have been explored in quiescent cells of Helianthus tuberosus induced to divide by auxin addition. Investigations confined to the first highly synchronous cell cycle of the tuber explants revealed that the relative activity of asparate carbam... |
The effects of calcium ions on lysine transport into cultured Wisconsin-38 tobacco cells were examined. In the presence of calcium, lysine was transported at a relatively low rate for 30 to 40 minutes followed by a period of increasing rates and subsequent stabilization at a higher rate after 2 to 3 hours. In the absen... |
Excised albedo tissue of citrus fruit (Citrus unshiu and Citrus hassaku) produced ethylene at an increasing rate in response to wounding and aging. The application of 1-aminocyclopropane-1-carboxylic acid (ACC) enhanced ethylene production in both the fresh and aged tissues, but this increase was greater in the aged ti... |
A rapid and simple, large-scale method for the purification of DNA-dependent RNA polymerase III (EC 2.7.7.6) from wheat germ is presented. The method involves enzyme extraction at low ionic strength, polyethyleneimine fractionation, (NH(4))(2)SO(4) precipitation, and chromatography on DEAE-Sepharose CL-6B, DEAE-cellulo... |
Studies with the seeds of soybean, navy bean, pea, and peanut were made to determine the extent of leakage of intracellular enzymes during imbition. Embryos with intact testae from all four species were found to leak detectable activities of either intracellular enzymes of the cytosol (glucose-6-phosphate dehydrogenase... |
Plasma membrane alterations in two tuber-bearing potato species during a 20-day cold acclimation period were investigated. Leaf-callus tissues of the frost-resistant Solanum acaule Hawkes ;Oka 3878' and the frost-susceptible, commonly grown Solanum tuberosum ;Red Pontiac,' were used. The former is a species that can be... |
Two forms (F-I and F-II) of 5'-nucleotidases (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) which catalyze the dephosphorylation of N(6)-(Delta(2)-isopentenyl)adenosine 5'-monophosphate and AMP to form the corresponding nucleosides were partially purified from the cytosol of wheat (Triticum aestivum) germ. Both the F... |
Enriched mitochondrial fractions isolated from durum wheat seedlings via differential centrifugation exhibited classical cyanide- or antimycin A-insensitive O(2) uptake which was inhibited by either salicylhydroxamic acid or propyl gallate. Further purification of this fraction using Percoll density gradients resulted ... |
Studies with purified mesophyll and epidermal protoplasts and bundle sheath strands have shown that the cyanogenic glucoside dhurrin (p-hydroxy-(S)-mandelonitrile-beta-d-glucoside) is localized in the epidermis of sorghum leaves whereas the enzymes involved in its degradation (dhurrin beta-glucosidase and hydroxynitril... |
Some properties of the polygalacturonase-elicitor from the filtrates of Rhizopus stolonifer cultures have been examined in an attempt to understand its mode of action as an elicitor of casbene synthetase activity in castor bean seedlings. Both the polygalacturonase activity and the elicitor activity are heat-labile wit... |
Acetyl coenzyme A (CoA) carboxylase activity of whole tissue homogenates and chloroplast preparations was analyzed as the acetyl-CoA-dependent incorporation of [(14)C]bicarbonate into an acid-stable product. The absolute requirement for ATP and MgCl(2), the complete inhibition with avidin, and end-product analysis were... |
Oleate Delta(12)-hydroxylase activity was measured in extracts of developing castor bean seeds. Most of the hydroxylase activity is associated with microsomes. However, when microsomes are washed, the activity is completely lost. Some (50%) of the activity can be restored by addition of the 100,000g supernatant to the ... |
Agmatine iminohydrolase (EC 3.5.3.12) was purified 7,300-fold from extracts of corn shoots by chromatographic separations on diethylaminoethyl-cellulose, Sephadex G-100, and agmatine-affinity column. The enzyme was homogeneous by the criteria of analytical gel electrophoresis. Molecular weight estimated by Bio-Gel P-20... |
Application of levulinic acid (LA), a competitive inhibitor of delta-aminolevulinic acid (ALA) dehydratase, to greening plant tissues causes ALA to accumulate at the expense of chlorophyll. 4,6-Dioxoheptanoic acid (DA), which has been reported to be an effective inhibitor of this enzyme in animal systems, has a similar... |
Carboxypeptidases from animal, plant, fungal, and bacterial sources were tested for their ability to bind to the carboxypeptidase inhibitor from Russet Burbank potatoes. Enzymes which participate in the degradation of dietary protein were partially purified from animal species as diverse as the cow and the limpet, and ... |
Large and rapid increases in the activities of two enzymes of general phenylpropanoid metabolism, phenylalanine ammonia-lyase and 4-coumarate:CoA ligase, occurred in suspension-cultured parsley cells (Petroselinum hortense) treated with an elicitor preparation from Phytophthora megasperma var. sojae. Highest enzyme act... |
A quantitative procedure for purifying small peptides from plant tissues, involving both ion-exchange and gel-exclusion chromatography, is described. Peptides were quantified and characterized by using the fluorescence reagents dansyl chloride and fluorescamine. Large pools of small peptides and amino acids have been i... |
The block in the electrogenic H(+) efflux produced by protein synthesis inhibitors in corn root tissue can be released or by-passed by addition of fusicoccin or nigericin. The inhibition also lowers cell potential, and the release repolarizes. Associated with the inhibition of H(+) efflux is inhibition of K(+) influx a... |
Carbon dioxide-dependent and 3-phosphoglycerate (PGA)-dependent O(2) evolution by isolated chloroplasts of wheat is inhibited by micromolar levels of iodoacetol phosphate (IAP). Loss of the activity is time-dependent and a higher concentration of PGA increases the half-time for inhibition (e.g. at 40 micromolar IAP the... |
Addition of sucrose to a solution bathing an excised developing soybean cotyledon causes a transient depolarization of the membrane potential, as measured using standard electrophysiological techniques. The magnitude of the depolarization is dependent on the concentration of both sucrose and protons in a manner which s... |
The effects of gibberellin in two wheat varieties, Nainari 60 and D6899, have been studied. D6899 is a dwarf wheat having a single locus mutation, the Rht 3 gene ("Tom Thumb" gene), which is located on chromosome 4A. When compared with the standard height wheat variety, Nainari 60, D6899 does not have a slowdown in cel... |
A membrane fraction which contains a blue light-sensitive flavin-cytochrome complex (Brain et al. 1977 Plant Physiol 59:948) has been partially purified by sucrose and Renografin gradient centrifugations. Assays for marker enzymes show that this membrane fraction is distinct from endoplasmic reticulum, golgi, and mitoc... |
Protein fractions from three selenium-tolerant and three selenium-sensitive Astragalus species, grown in the presence of [(75)Se]selenate, were analyzed for their selenium content. Though tolerant species are known to accumulate considerably more selenium than do sensitive plants, protein fractions from the three selen... |
Selenomethionine and methionine were compared as substrates for in vitro aminoacylation, ribosome binding, and peptide bond formation with preparations from wheat germ. Selenomethionine paralleled methionine in all steps of the translation process except peptide bond formation. Peptide bond formation with the initiatin... |
Selenium-accumulator plants synthesize selenium compounds that differ from those produced by nonaccumulators. To determine if there are any subcellular differences between accumulators and nonaccumulators in the use of selenomethionine in vitro, polysomes from Astragalus crotalariae (accumulator) and Astragalus lentigi... |
Photosystem II-dependent cyclic photophosphorylation activity produced by addition of p-phenylenediamines to KCN-Hg-NH(2)OH-inhibited chloroplasts is the product of two separate reactions when a proton/electron donor is the catalyst. The activity observed with an electron donor as catalyst consists of a single reaction... |
Phosphatidylethanolamine synthesis by CDP-ethanolamine:1,2-diacylglycerol ethanolaminephosphotransferase (EC 2.7.8.1) from the endoplasmic reticulum of castor bean (Ricinus communis L. var. Hale) endosperm was characterized. The Michaelis-Menten constant of the enzyme for CDP-ethanolamine was approximately 8.0 micromol... |
Protein from the jack bean, peanut, soybean and kidney bean seeds were extracted with a solution containing 9.3 molar urea, 5 millimolar K(2)CO(3), 0.5% dithiothreitol and 2% Nonidet P-40 and then subjected to two-dimensional gel electrophoresis. After electrophoresis, the slab gels were stained with a variety of (125)... |
Mesophyll protoplasts were isolated from the leaves of wheat and corn seedlings. After purification the protoplasts were judged to be free of contaminating proteases in the isolation enzymes based on specific activity of the proteases in comparison to leaf tissue and their response to inhibitors that "differentiated" b... |
Polyphenol oxidase activity (E.C. 1.14.18.1) has been found in two enzyme species isolated from thylakoid membranes of spinach chloroplasts. The proteins were released from the membrane by sonication and purified >900-fold by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography. The enzymes a... |
Seedings of Vicia faba were grown for four weeks at two different light intensities (55 and 105 watts per square meter) in a saline (50 millimolar NaCl) and nonsaline nutrient solution. NaCl salinity depressed growth and restricted protein formation, CO(2) assimilation, and especially the incorporation of photosynthate... |
Cholesteryl hemisuccinate has been incorporated into pea chloroplast thylakoids to investigate the relationship between fluidity and functioning of this membrane system. Levels of sterol which increased the apparent viscosity of the membrane, estimated by fluorescence polarization measurements using the lipophilic prob... |
Translation products of poly(A) mRNA isolated from Lemna gibba L. G-3 include a major polypeptide of 32,000 daltons which is immunoprecipitated by antiserum to chlorophyll a/b-protein from Chlamydomonas. This 32,000 dalton polypeptide represents a precursor to the light-harvesting chlorophyll a/b-protein of molecular w... |
Cell-free protein synthesizing systems have been used to study the developmental changes in the synthesis of chloroplast proteins in the cotyledons of cucumber seedlings grown in the light or in the dark. Escherichia coli and wheat germ in vitro protein synthesizing systems have been used to assay the changes in the le... |
Spinach leaf discs accumulated betaine when exposed to a mannitol solution of -20 bars. The accumulation was 12 micromoles per gram original fresh weight in a 24-hour period.Betaine-aldehyde dehydrogenase (EC 1.2.1.8) was assayed in various subcellular fractions prepared from spinach leaves, and it was found only in th... |
Urease activity of tobacco XD cells (1U cells) had undergone a 4-fold increase (4U cells) during a year of growth on urea (Skokut and Filner 1980 Plant Phvsiol 65: 995-1003). A clone of 4U cells gave rise to 12U cells during another year of growth on urea. The doubling time of 12U cells on urea is 2.2 days, compared to... |
Soluble starch synthase and starch-branching enzymes in extracts from kernels of four maize genotypes were compared. Extracts from normal (nonmutant) maize were found to contain two starch synthases and three branching enzyme fractions. The different fractions could be distinguished by chromatographic properties and ki... |
Studies of ribulose-1,5-bisphosphate (RuBP) carboxylase from taxonomically diverse plants show that the enzyme from C(3) and crassulacean acid metabolism pathway species exhibits lower K(m)(CO(2)) values (12-25 micromolar) than does that from C(4) species (28-34 micromolar). RuBP carboxylase from aquatic angiosperms, a... |
Biosynthesis of ent-kaurene was investigated in extracts of cell suspension cultures and seedlings of castor bean. Both cell-free extracts contain an inhibitor of kaurene synthetase. The inhibition affects mainly the cyclization of geranylgeranyl pyrophosphate to copalyl pyrophosphate (activity A) and has little or no ... |
alpha-Galactoside binding proteins were isolated from cellular membranes of mint and tobacco as well as two clones of sugarcane which differ in their sensitivity to helminthosporoside, a toxic galactoside. Sodium trichloroacetate was used to disrupt membranes after which the proteins were purified using a melibiose-Sep... |
A wilt-inducing peptidorhamnomannan produced by Ceratocystis ulmi, the causative agent in Dutch Elm disease, has been subjected to additional chemical and physical characterization. Gel filtration, reductive beta elimination, hydrofluoric acid deglycosylation, and ultracentrifugation experiments provide evidence that t... |
Purified ribulose-1,5-bisphosphate carboxylase/oxygenase in 50% saturated (NH(4))(2)SO(4) was stable when frozen as small beads in liquid nitrogen and stored at -80 C. When stored as a slurry at 4 C most of the activity was lost within four weeks. This loss was due not only to enzyme polymerization. Activity in old pre... |
The rate of protein degradation in Zea mays leaves has been estimated by using tritiated water and [(3)H]acetic anhydride as the labeling agents. Both methods circumvent many of the problems usually associated with measuring protein degradation in plants. The half-life of ribulose-1,5-bisphosphate carboxylase protein i... |
Glutathione dehydrogenase (EC 1.8.5.1) was partially purified from pea shoots. The pH optimum was 7.6. The K(m) values for GSH and dehydroascorbate were 4.4 and 0.44 millimolar, respectively. The enzyme was inhibited by iodoacetate and CuSO(4) but not significantly by ZnCl(2) or NaN(3). Part of the total enzyme activit... |
The ammonium-inducible NADP-specific glutamate dehydrogenase of Chlorella sorokiniana was shown to require light for both its induction by ammonia in uninduced cells, and its continuous accumulation in fully induced cells. Addition of ammonia to uninduced cells in the light resulted in a 35-minute induction lag followe... |
The nitrate reductase activity of 5-day-old whole corn roots was isolated using phosphate buffer. The relatively stable nitrate reductase extract can be separated into three fractions using affinity chromatography on blue-Sepharose. The first fraction, eluted with NADPH, reduces nearly equal amounts of nitrate with eit... |
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