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When a stationary phase cell culture of Arachis hypogaea L. is diluted into fresh media, there occurs a 10-fold increase in the rate of protein synthesis. The kinetics of the activation of amino acid-incorporating capacity show a lag of 10 to 15 minutes with maximal activity reached at 2 hours after dilution. The activ... |
Particulate enzyme preparations from tobacco seedlings (Nicotiana tabacum L.) were used in the synthesis of steryl glycoside. The data obtained by measuring cholesterol-4-(14)C incorporation generally agree with results obtained with UDP-glucose-(14)C. The in vitro reaction was linear for the first 10 minutes and had a... |
The ability of intact spinach (Spinacia oleracea) chloroplast preparations to catalyze CO(2) fixation and photophosphorylation was examined. Under conditions optimal for CO(2) fixation, only poor photophosphorylation was observed. Conditions optimal for photophosphorylation were found to be highly inhibitory to the CO(... |
The capacity for biosynthesis of hot alkali-insoluble products using uridine diphosphate (UDP)-glucose and guanosine diphosphate (GDP)-glucose as substrate has been studied in isolated cotton fibers harvested at various stages of development following anthesis. During the period of rapid elongation and primary wall syn... |
Cell-free extracts of Chlorella pyrenoidosa contained two enzymes capable of oxidizing d-lactate; these were glycolate dehydrogenase and NAD(+)-dependent d-lactate dehydrogenase. The two enzymes could be distinguished by differential centrifugation, glycolate dehydrogenase being largely particulate and NAD(+)-d-lactate... |
The enzymic utilization of cytidine diphosphoethanolamine in the synthesis of phosphatidylethanolamine is localized in the microsomal fraction of spinach (Spinacia oleracea) leaves. The metal ion requirement can be satisfied by Mn(2+) (saturation approximately 0.6 mm) or Mg(2+) (saturation approximately 25 mm). The enz... |
Several aspects of wound healing in tuber tissue of potato (Solanum tuberosum var. Kennebec), known to require protein synthesis, are inhibited by 2,4-dichlorobenzyltributylphosphonium chloride (Phosphon D). Cell division was completely blocked by 60 mum Phosphon and markedly reduced by concentrations as low as 3 mum. ... |
Several cell wall-bound glycosidases present in Avena sativa coleoptiles were assayed by following the hydrolysis of p-nitrophenyl-glycosides. Particular emphasis was placed on characterizing some parameters affecting the activity of beta-galactosidase. The pH optimum of this enzyme is 4.5 to 5.5; it is sensitive to co... |
The assimilation of nitrite leading to de novo synthesis of amino nitrogen in a chloroplast-enriched fraction isolated from freshly harvested young spinach (Spinacia oleracea L.) leaves was demonstrated. The preparations showed approximately 55% intact chloroplasts as determined by light scattering properties and fixed... |
Two forms of malate dehydrogenase of widely differing molecular weight have been examined from primary leaves of Phaseolus vulgaris. In addition to the normal 69,000 molecular weight enzyme, an unusual form of 280,000 molecular weight may be detected by sucrose density gradient centrifugation or gel filtration with Sep... |
Protochlorophyllide and chlorophyll(ide) holochromes (Pchl-H and Chl-H) were extracted from dark-grown and greening seedlings with saponin and partly purified by ammonium sulfate fractionation. Sephadex gel filtration in the presence of saponin showed that the photoactive saponin Pchl-H from dark-grown leaves of bean (... |
An NAD-linked dehydrogenase from Chlorella pyrenoidosa Chick catalyzing the conversion of l-proline to Delta(1)-pyrroline-5-carboxylic acid was partially purified. Delta(1)-Pyrroline-5-carboxylic acid was identified as the product by co-chromatography of it and its o-aminobenzaldehyde derivative with authentic compound... |
Degradation of the major storage proteins in maize endosperm, zein and glutelin, begins during the 2nd day of germination. The protein most abundant in the mature endosperm is degraded most rapidly. The patterns of protein loss are essentially similar in germinating seeds and excised endosperms. Cycloheximide, added at... |
Amylases from incubated aleurone layers or from starchy endosperm of barley seeds (Hordeum vulgare L. cv. Himalaya) were investigated using acrylamide gel electrophoresis and analytical gel filtration with Sephadex G-200. Electrophoresis of amylase from aleurone layers yields seven visually distinct isozymes with an es... |
Synthesis of germ tube wall is a major quantitative event during germination penetration of fungi on host plants, but little is known of germ tube composition or metabolic regulation. Sonic oscillation was used to separate germ tubes from germinating uredospores of Uromyces phaseoli var. typica. Uniformly (14)C-labeled... |
Cytoplasmic and chloroplast ribosomal proteins were isolated from Euglena gracilis and analyzed on polyacrylamide gels. Cytoplasmic ribosomes appear to contain 75 to 100 proteins ranging in molecular weight from 10,200 to 104,000, while chloroplast ribosomes appear to contain 35 to 42 proteins with molecular weights ra... |
In tobacco (Nicotiana Tabacum) pith, sweet potato (Ipomoea batatas), and carrot (Daucus carota) storage roots, differences were found between cell wall and protoplast peroxidases in their isoenzyme patterns, activity, and reaction to tissue injury.In the pith of elongating tobacco internodes, 90% of total activity was ... |
The development of the mitochondrial enzymes fumarase and succinate dehydrogenase has been followed in Euglena cultures division-synchronized by 14-hour light periods alternating with 12-hour dark periods. The activity of both enzymes was unaltered over the light phase, doubled in early dark phase, and thereafter remai... |
Metabolic readjustments after a change from long days to short days appear, in Kalanchoe blossfeldiana, to be achieved through the operation of two main mechanisms: variation in enzyme capacity, and circadian rhythmicity. After a lag time, capacity in phosphoenolpyruvate carboxylase and capacity in aspartate aminotrans... |
The ricinine content of etiolated seedlings of Ricinus communis increased nearly 12-fold over a 4-day period. In plants quinolinic acid is an intermediate in the de novo pathway for the synthesis of pyridine nucleotides. The only known enzyme in the de novo pathway for pyridine nucleotide biosynthesis, quinolinic acid ... |
An NADP(+)-dependent dihydroxyacetone reductase, which catalyzes specifically the reduction of dihydroxyacetone to glycerol, has been isolated from the halophilic alga Dunaliella parva. The enzyme has been purified about 220-fold. It has a molecular weight of about 65,000 and is highly specific for NADPH. The pH optima... |
Nitrate reductase activity and protein percentage of various tree parts of two Populus clones were determined in relation to nitrate ion activity. Nitrogen was supplied as NH(4)NO(3) in a nutriculture system. Wisconsin-5 had significantly greater nitrate reductase activity than Tristis No. 1. Protein percentages of lea... |
Concentrations of cycloheximide as low as 3 mug/ml inhibited incorporation of labeled orotic acid or uridine into RNA cytidylic acid of soybean (Glycine max) hypocotyl sections. Even lower concentrations of this well known protein synthesis inhibitor interfered with conversion of labeled cytidine into RNA uridylic acid... |
The in vitro instability of nitrate reductase (EC 1.6.6.1) activity from leaves of several species of higher plants was investigated. Decay of activity was exponential with time, suggesting that an enzyme-catalyzed reaction was involved. The rate of decay of nitrate reductase activity increased as leaf age increased in... |
The results presented demonstrate that microbial pathogens of plants have the ability to secrete proteins which effectively inhibit an enzyme synthesized by the host; an enzyme whose substrate is a constituent of the cell wall of the pathogen. The system in which this was discovered is the anthracnose-causing fungal pa... |
At concentrations of up to 300 mug/ml both d-threo- and l-threo-chloramphenicol act as energy transfer inhibitors in spinach chloroplasts, in that they inhibit both phosphorylation and phosphorylating electron transport, without affecting the nonphosphorylating electron transport which occurs either in the absence of a... |
A galactolipid lipase has been isolated and partially purified from the chloroplast fraction of the primary leaves of Phaseolus vulgaris var. Kentucky Wonder. The lipase hydrolyzed monogalactosyl diglyceride rapidly and phosphatidyl choline relatively slowly. Triolein and p-nitrophenyl stearate were not hydrolyzed.Spin... |
A flexible analytical system which allows for the continuous potentiometric monitoring of the disappearance of an electrochemical species, ferrocyanide, by the peroxidase enzyme is described. The ability of peroxidase to mediate the oxidation of indole-3-acetic acid is followed by observing the competition of indole-3-... |
Cellulase (beta-1, 4-glucan-glucanohydrolase EC 3.2.1.4) activity in the abscission zone of red kidney bean (Phaseolus vulgaris) was previously shown to exist in at least two different molecular forms. The form of the enzyme which has an isoelectric point of 4.5 is present in both abscising and nonabscising tissue and ... |
Fresh weight and dry weight as well as quantitative and qualitative protein changes in the developing soybean (Glycine max) seed were described from 12 days after flowering until maturity. The seed proteins were separated on sucrose density gradients into three major fractions, having average sedimentation coefficients... |
The distribution and localization of cholinesterase in Phaseolus aureus, Glycine max, and Pisum sativum is described. The enzyme is present in roots, leaves, stems, root callus tissue, root cells suspension cultures, and root nodules. Cholinesterase in roots is found primarily in the cell wall. In cell fractionation ex... |
Four enzyme-containing fractions were separated by ammonium sulfate fractionation of 2-day, postbreaker tomato (Lycopersicon esculentum L. cv. Manhattan). The pH optima and substrate specificities are reported. The enzymes were identified as a nonspecific beta-glucosidase, an exo-beta-1,4-glucanase, and two endocellula... |
The ATP content of isolated wheat (Triticum aestivum L. var. Polk) embryos increases 5-fold during the first 30 minutes and 10-fold during the first hour of germination to 80% of maximum. The ATP level remains at approximately 800 nanomoles per gram of tissue during the next 15 hours. ADP, AMP, and total adenosine phos... |
Mitochondria and glyoxysomes were isolated from scutella of maize (Zea mays L.) by density gradient centrifugation. Citrate synthetase was partly solubilized from the organelles by sonication. The sonicated organelle suspensions were centrifuged at high speed, and the supernatants were used as enzyme preparations witho... |
Nitrate reductase activity is most commonly assayed by measurement of product formation. Excess NADH and factor(s) present in the enzyme extract that interfere with the diazotization and azo color complex of nitrite cause a depression of apparent nitrate reductase activity. Two postassay treatments were found that mark... |
Phosphoenolpyruvate carboxylase (EC 4.1.1.31), partially purified from spinach (Spinacia oleracea) leaves, is inhibited by SO(3) (2-) ion. The inhibition is competitive or mixed type with respect to HCO(3) (-) (Ki = 17 mm), and noncompetitive with respect to phosphoenolpyruvic acid (Ki = 11 mm), Mg(2+) (Ki = 10 mm), an... |
Chloroplastic and cytoplasmic forms of pea (Pisum sativum L.) leaf glucose-6-P dehydrogenase can be separated by gel electrophoresis. Both forms are found in etiolated seedlings. When light-grown plants are illuminated or when crude extracts are treated with dithiothreitol, the chloroplastic and cytoplasmic forms of th... |
Cytochromes b(553), b(557), and b(562) of mung bean (Phaseolus aureus) mitochondria become partially reduced with endogenous substrate on addition of antimycin A to the aerobic mitochondrial suspension. Addition of ATP causes partial reoxidation of the three cytochromes. This partial oxidation by ATP is inhibited by ol... |
During the transition from the aerobic steady state with succinate as substrate to anaerobiosis, in suspensions of skunk cabbage (Symplocarpus foetidus) mitochondria treated with antimycin A, cytochrome b(562) becomes reoxidized to the extent of about 20%, synchronously with the reduction of cytochrome c(549). This reo... |
Protein-rich subcellular particulates were isolated by zonal centrifugation from homogenates of endosperms of normal, opaque-2, and floury-2 mutant corn (Zea maize) kernels at different stages of development. In early stages the high lysine mutants vary from normal corn by greater production of a glutelin protein not a... |
The alga Chlorogonium elongatum was grown autotrophically or heterotrophically on acetate. Cells harvested in the logarithmic phase of growth were disrupted, and the whole homogenates were fractionated on sucrose gradients. Protein and enzyme determinations carried out on the fractions led to the following conclusions.... |
Treatment of slices of young pea leaves (Pisum sativum) with muM solutions of alpha-chlorallyl diethyldithiocarbamate, dichloroallyl diisopropylthiocarbamate, or S-ethyldipropylthiocarbamate resulted in inhibition of incorporation of [1-(14)C]acetate into C(31) alkane and C(31) secondary alcohol, very little effect on ... |
Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric CO(2) levels ranging from 100 to 800 mul/l decreased nitrate accumulation and nitrate reductase activity. Plants pretreated with CO(2) in the dark and maintained in an atmosphere containing 100 mul/l CO(2) accumulated 7-fold more nitrate and had... |
Ammonium sulfate chromatography has been employed to separate glyceraldehyde 3-phosphate dehydrogenases (GPD) of Sinapis alba cotyledons of various developmental stages. Cotyledons of dark-grown seedlings possess one major NAD-specific enzyme designated NAD-GPD I. Irradiation with continuous far red light leads to a st... |
Lead (300 mum) and cadmium (18 mum) inhibit pod fresh weight in soybeans (Glycine max L.) by 35%. Eighteen micromolar cadmium caused a 30% decline in nitrogenase activity by day 52 (the day on which maximum activity was measured) and a 71% inhibition by day 59. The heavy metals depressed photosynthetic rates; when phot... |
The following reaction leading to the synthesis of the trisaccharide umbelliferose was demonstrated in an enzyme preparation from leaves of Aegopodium podagraria L.: sucrose + UDP-gal-(14)C --> umbelliferose-(14)C + UDP. Neither galactinol nor galactose 1-phosphate could replace UDP-gal. Among 10 different sugars teste... |
The influence of indoleacetic acid, 0.03% CO(2), and malate on protein metabolism of etiolated Avena sativa coleoptile sections has been investigated. All three were found to elevate both the rate of incorporation of labeled leucine into protein, and the level of soluble protein. The combination of indoleacetic acid an... |
An alternative to the leaf disk system for studies of the metabolism of senescence is described. The progress of senescence of soybean (Glycine max L.) cotyledons is arrested when the epicotyl is removed. Epicotyl removal at 16 or 17 days reversed the decline in nucleic acid, protein, and chlorophyll content in the cot... |
Influences of light and darkness on l-phenylalanine ammonia-lyase activity of black locust (Robinia pseudoacacia) seedlings were studied. Light initiates both an increase in enzyme activity (or enzyme synthesis) and a subsequent decrease in activity. These dual influences of light create cyclic changes in l-phenylalani... |
The effect of specific levels of induced water stress on the root exudation of (14)C from 9-month-old and 12-month-old ponderosa pine (Pinus ponderosa Laws.) seedlings was examined. Polyethylene glycol (PEG-4000) was used to decrease root solution water potentials by 0, -1.9, -2.6, -5.5, -9.6 and -11.9 bars in either a... |
Mitochondria were isolated from glucose-bleached Chlorella protothecoides Krüger, Indiana strain 25. These mitochondria oxidized succinate, NADH, and l-malate at high rates. Oxygen uptake with these substrates was partially inhibited by 1 mmm-chlorobenzhydroxamic acid (mCLAM). Respiratory control was seen with succinat... |
When root tissue of sweet potato (Ipomoea batatas Lam.) was sliced, acid invertase activity, initially absent in freshly sliced tissue, appeared after a 3- to 6-hour lag phase, rapidly reached a maximum in 18 hours, and thereafter decreased. The increase in invertase activity was accompanied by a decrease in sucrose co... |
Protein kinase (ATP:protein phosphokinase) has been found associated with ribosomes prepared from 5-day-old etiolated pea shoots and sterile cultures of Lemna minor. The enzyme catalyzes the phosphorylation of ribosomal proteins in vitro and may be involved in the formation of phosphoproteins in the ribosomes in vivo. ... |
Preliminary work revealed that nitrate reductase in crude extracts prepared from leaves of certain corn genotypes as well as soybeans could utilize NADPH as well as NADH as the electron donor. Isoelectric focusing and diethylaminoethyl cellulose chromatography confirmed previous findings that NADH and NADPH activities ... |
The temperature dependence of carotenoid synthesis in Neurospora crassa was investigated. The primary light reaction is independent of temperature, but the amount of carotenoid pigment which subsequently accumulates in the dark is strongly dependent on the temperature during the dark incubation. Carotenoid synthesis sh... |
The synthesis of phosphatidylglycerol in castor bean (Ricinus communis var. Hale) endosperm tissue was found to be located in both the endoplasmic reticulum and mitochondrial fractions separated on sucrose density gradients. The enzyme of both fractions attained maximum activity at 5 mm Mn(2+), 0.075% Triton X-100, and... |
Uridine diphosphate glucose pyrophosphorylase was isolated separately from Avena sativa leaves, roots, and etiolated coleoptiles and purified by ammonium sulfate fractionation, DEAE-Sephadex chromatography and polyacrylamide gel electrophoresis. There was no difference in the enzyme from the different tissue types with... |
Ethylene-induced abscission in flower pedicels of Nicotiana tabacum L. cv. Little Turkish causes a progressive increase in peroxidase activity during the first 4 hours of a 5-hour time course ethylene treatment period, with decrease in peroxidase activity occurring between 4 hours and 5 hours, when the supernatant extr... |
In cotyledons of germinating cotton (Gossypium hirsutum L. var. Stoneville 213) seedlings, in the dark, isocitric lyase (EC 4.1.3.1) activity peaks after 2 days and thereafter slowly declines to a negligible value after 8 days. The maximum activity of this enzyme in cotyledons of 2-day-old seedlings was 16.2 mumoles of... |
Research on the mode of action of auxin in the promotion of growth has shown that auxin treatment leads to hydrogen ion secretion and wall acidification. It has recently been reported that auxin stimulates cell wall beta-galactosidase activity in Avena coleoptiles, presumably by causing cell wall acidification, since t... |
The correlations between ATP concentration in corn (Zea mays) root tissue and the rate of phosphate absorption by the tissue have been examined. Experimental variation was secured with 2,4-dinitrophenol, oligomycin, mersalyl, l-ethionine, 2-deoxyglucose, N(2) gassing and inhibition of protein synthesis. It is concluded... |
Rhythmic leaflet movement in Albizzia is controlled by rhythmic K(+) flux in pulvinal motor cells. The angle assumed by darkened leaflets during the open phase of the rhythm can be altered by various compounds and changes in temperature; such treatments are ineffective during the closed phase. In all cases, effects on ... |
Action and uptake of azides, nitrates, nitrites, hydroxylamines, and ammonium salts were measured on germination of Amaranthus albus, Lactuca sativa, Phleum pratense, Barbarea vulgaris, B. verna, and Setaria glauca seeds. Nitrate and nitrite reductase activities were measured in vivo for each of these kinds of seeds. A... |
Glyceraldehyde 3-phosphate dehydrogenases (EC 1.2.1.12 and 1.2.1.13) have been purified from the seed, root, etiolated, and green shoot of peas (Pisum sativum). These enzymes are tetramers of 140,000 daltons, with subunits of 35,000 daltons. The enzymes differ in isoelectric point. The seed enzyme has a pI of 5.1, and ... |
Biosynthesis of glucans occurred in cell-free fractions isolated from onion stem (Allium cepa L.) enriched in either dictyosomes or plasma membranes. beta-1,3- and beta-1, 4-Glucans were synthesized in differing proportions and at different rates as the concentration of uridine diphosphoglucose or the proportion of dic... |
Two major peaks of RNA polymerase activity have been routinely separated by diethylaminoethyl cellulose chromatography following solubilization from soybean (Glycine max L. var. Wayne) chromatin. The relative amounts of these two peaks depend upon the manner in which the chromatin is purified. Pelleting the chromatin t... |
Kaempferol (3, 5, 7, 4'tetrahydroxyflavone) inhibited the rate of state 3 substrate oxidation, but not the state 4 rate. This, along with the kaempferol inhibition of substrate-driven calcium-phosphate deposition, provided evidence that kaempferol was acting specifically on the phosphorylation mechanism and not on elec... |
Ornithine carbamoyltransferase (EC 2.1.3.3) activity was detected in apple (Pyrus malus L.) leaf tissue from early June to November. Total activity remained relatively constant at 4.1 mumoles citrulline produced per hour per 10 cm(2) until mid-October when it sharply doubled. Following the first frost of the autumn, th... |
Park and co-workers (Annu. Rev. Plant Physiol. 22: 395-430) have suggested that stroma lamellae, which perform only photosystem I contain a developing photosystem II which becomes functional upon the folding of these membranes to form grana stacks.The present study was undertaken to test this hypothesis. The lipid and ... |
Hormones which inhibit senescence of Rumex leaf tissue in the dark include gibberellin A(3), and the cytokinins 6-benzylamino purine and zeatin. These hormones inhibit respiratory metabolism in this tissue, but do not change the pattern or total amount of oxygen consumption during senescence. Abscisic acid, a senescenc... |
This study demonstrates that isolated corn (Zea mays L. Wf9 xM14) shoot mitochondria will accumulate calcium phosphate crystals in vitro that are comparable to those observed in both in vivo and in vitro animal mitochondria. The intensity of deposition, as observed by electron microscopy, increased with incubation time... |
It has been suggested by others that the spectrophotometric assay of phenylalanine ammonia-lyase based on changes in absorbance at 290 nm may be complicated by a side reaction involving transamination from phenylalanine onto alpha-keto acids. This would lead to the production of phenylpyruvate which would spontaneously... |
A factor which precipitates amylose has been isolated from Lentinellus ursinus (Fr.) Kühner fruit bodies. This factor could be a protein or a polypeptide. Glucose, maltose, and amylopectin do not affect the binding of amylose. Amylose binding is unaffected by temperature (4 to 40 C) or pH (6 to 8.5). |
Stearyl-acyl carrier protein desaturase (EC 1.14.99.6), present in the stroma fraction of spinach (Spinacia oleracea) chloroplasts, rapidly desaturated enzymatically prepared stearyl-acyl carrier protein to oleic acid. No other substrates were desaturated. In addition to stearyl-acyl carrier protein, reduced ferredoxin... |
When specifically labeled glutamate-1-(14)C was provided to 4-day-old rose cells, 87.6% of the (14)C in glutamate recovered from protein was in the number 1 carbon atom of the glutamate molecule. It was concluded that newly absorbed glutamate was incorporated directly into protein without any prior metabolism.A double ... |
The effect of potassium supply of Vicia faba on the fixation of molecular nitrogen by root nodules was studied by using (15)N-labeled molecular nitrogen. Plants well supplied with potassium showed higher contents of (15)N in the soluble amino fraction and in the protein fraction of various plant organs as compared with... |
Cotton plants (Gossypium hirsutum. Linn. var. Sankar 4) were grown at normal and toxic levels of substrate manganese, and the altered metabolism of manganese toxic plants was studied. The tissues of plants exposed to toxic levels of manganese had higher activities of peroxidase and polyphenol oxidase, and the activitie... |
Activities of glucose 6-phosphate, 6-phosphogluconate, and isocitrate dehydrogenases, together with intermediate levels of the glycolytic pathway and the pentose phosphate cycle, were measured throughout a year in the living bark of poplar (Populus gelrica). Shoots, immediately after budding (early May), contained very... |
Ribulose 1,5-diphosphate carboxylase, when activated by preincubation with 10 mm MgCl(2) and 1 mm bicarbonate in the absence of ribulose 1,5-diphosphate, can be further activated about 170% with 0.5 mm NADPH present in the preincubation mixture. NADP(+), NADH, and NAD(+) are ineffective. The activation by NADPH is comp... |
A method of purification of pyruvate kinase (EC 2.7.1.40) from light-grown Euglena gracilis var. bacillaris was developed which yielded an enzyme preparation purified 115-fold over crude extracts. During organelle formation, levels of pyruvate kinase in extracts prepared from cells engaged in light-induced chloroplast ... |
THE ASSIMILATORY NITRATE REDUCTASE (NADH: nitrate oxidoreductase, E.C. 1.6.6.2.) from the marine diatom Thalassiosira pseudonana, Hasle and Heimdal, has been purified 200-fold and characterized. The regulation of nitrate reductase in response to various conditions of nitrogen nutrition has been investigated.Nitrate red... |
Kinetin-induced changes in dry weight, soluble protein content, delta-aminolevulinic acid dehydratase activity, and chlorophyll content of two clones of Nicotiana tabacum L. callus were studied. Kinetin brought about a marked increase in the delta-aminolevulinic acid dehydratase activity of nongreen tissue just before ... |
Production of carbohydrases by Alternaria solani is inhibited by glucose under low growth conditions. In an enriched medium, glucose has little effect on the production of polygalacturonase and cellulase while it still suppresses production of beta-glucosidase. Low levels of all three enzymes were produced in the absen... |
The increase in phenylalanine ammonia-lyase (PAL) activity in strawberry (Fragaria vesca var. WSU-1232) leaf disks required wounding, sucrose, and light and was cycloheximide-sensitive. In injured leaves and in leaf disks, the highest PAL activity was detected nearest the wounded tissues. Without wounding, no increase ... |
Kinetic properties of soybean net photosynthetic CO(2) fixation and of the carboxylase and oxygenase activities of purified soybean (Glycine max [L.] Merr.) ribulose 1, 5-diphosphate carboxylase (EC 4.1.1.39) were examined as functions of temperature, CO(2) concentration, and O(2) concentration. With leaves, O(2) inhib... |
Excised pea pods responded similarly to both the invasion of plant pathogenic fungi and the presence of bean tissue, bean pollen, and mouse tumor cells by synthesizing pisatin and by developing a characteristic yellow-green fluorescence. Both responses were dependent on RNA and protein synthesis. Conversely, the foreig... |
Three types of activation of 4-hydroxycinnamate hydroxylase have been observed in extracts of Sorghum bicolor. One involves the elimination of a lag period either by increasing the enzyme concentration or by the addition of a catalytic amount of caffeic acid. Two involve increases after freezing of incubation mixtures ... |
The activity of several photosynthetic enzymes was unaltered by exposure of sorghum or maize to low temperatures (10 C) and light (170 w m(-2)). Two light-activated C(4)-pathway enzymes, NADP-malate dehydrogenase and pyruvate Pi dikinase, were reduced in activity, and this was largely attributable to a loss of enzyme r... |
Glucose oxidase (from Aspergillus niger), glucoamylase (from Rhizopus spp.), and cellulase (from Aspergillus niger) of fungal origin are all glycosylated proteins. Dehydration of the three enzymes to a range of water potentials did not affect their activity. However, when more than 10% of the carbohydrate associated wi... |
A study of energy state and chemical composition of pod walls and seeds of maturing rape (Brassica napus L.) was conducted on two varieties, Victor and Gorczanski. Total adenosine phosphates, ATP, and adenylate energy charge increased with increasing cell number and cellular synthesis during the early stages, remained ... |
A glucosyl and a glucosyl-glucan transferase activity from spinach (Spinacia oleracea L. var. Matador) leaves have been partially purified and characterized. The latter activity (fraction 1 after diethylaminoethylcellulose chromatography) is responsible for the transfer of glucosyl as well as of maltosyl, maltotriosyl,... |
Purified glutamine synthetase from pea seedlings was most active with Mg(2+) as the metal activator, but Mn(2+) and Co(2+) were 45 to 60% and 30 to 45% as effective, respectively, when assayed at the optimal pH for each cation. The Mg(2+) saturation curve was quite sigmoid, and evidence indicates that MgATP is the acti... |
A three-phase, discontinuous sucrose gradient yielded two distinct fractions of envelope membranes from spinach (Spinacia oleracea L.) chloroplasts. Their buoyant densities were 1.08 g cm(-3) and 1.11 g cm(-3). Electron micrographs showed the lighter and heavier fractions to consist primarily of single and double membr... |
Cell-free extracts from gibberellic acid-treated barley (Hordeum vulgare L. cv. Himalaya) aleurone layers show phosphorylcholine glyceride transferase activity greater than that from control layers. The increase in activity is not prevented by a mixture of amino acid analogs nor by cordycepin under conditions in which ... |
The seed coat of Pisum elatius is normally impermeable to water. When seeds are dried in the absence of oxygen their coats are totally permeable to water. Structural differences are observed between permeable and impermeable seed coats. In the genus Pisum, species with normally impermeable seed coats have a high conten... |
NADH-nitrate reductase activity in excised embryos of Agrostemma githago develops in response to nitrate as well as benzyladenine. Induction of nitrate reductase by benzyladenine was much more susceptible to inhibition by a mixture of amino acid analogues and by cordycepin than induction by nitrate. In contrast, only i... |
A soluble enzyme that transfers d-glucose from uridine diphosphate d-glucose to low molecular weight hydroxyl compounds has been discovered in germinating mung bean (Phaseolus aureus) seeds and purified 220-fold. Phenol and n-butyl alcohol are the most reactive aceptors examined. The reactivities of various acceptors a... |
Incubation of mature sweet corn kernels of Zea mays in dilute solutions of (14)C-labeled indole-3-acetic acid leads to the formation of (14)C-labeled esters of myo-inositol, glucose, and glucans. Utilizing this knowledge it was found that an enzyme preparation from immature sweet corn kernels of Zea mays catalyzed the ... |
Phloem loading in source leaves of sugar beet (Beta vulgaris, L.) was studied to determine the extent of dependence on energy metabolism and the involvement of a carrier system. Dinitrophenol at a concentration of 4 mm uncoupled respiration, lowered source leaf ATP to approximately 40% of the level in the control leaf ... |
The proteolytic activities of alpha-chymotrypsin, trypsin, pepsin, bromelain, and an extract from germinating pumpkin seeds (Cucurbita moschata) were determined by their ability to effect the release of 1-anilino-8-naphthalenesulfonate bound to internal hydrophobic sites in intact protein substrates. Casein, glyceralde... |
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