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Effects of zeatin on amino acid and sugar contents of detached radish (Raphanus sativus L.) cotyledons were investigated to determine if accumulation of these solutes contributes to cytokinin-enhanced growth. Protein and amino acid levels were not significantly affected, but in cotyledons incubated in light the hormone... |
Chlorophyll levels in l-cm sections of the youngest fully expanded leaves of normal (Y) Festuca pratensis L. declined almost to zero over a period of 6 days after excision. Chlorophyll in a mutant genotype (NY) remained near the initial level for the whole of this period. Abscisic acid promoted pigment loss in Y but ha... |
Cutting of tissue sections induces RNase (EC 2.7.7.16) activity (phase I) in white turnip (Brassica rapa L. var. rapa) which peaks in 4 or 7 hours and then declines rapidly (phase II). The increase is inhibited by cycloheximide; also RNase from tissue bathed in 99.8% D(2)O during phase I underwent a large increase in b... |
Low concentrations of cycloheximide added to rose suspension culture cells stopped protein synthesis and drastically reduced the incorporation of (14)C into arginine, lysine, isoleucine, threonine, and valine. |
Inhibition by cycloheximide of sulfate transport in both barley roots (Hordeum vulgare L.) and potato tuber (Solanum tuberosum L.) increases with increasing inhibitor concentration only to a limited extent, depending on the length of the tissue incubation with the inhibitor. In contrast to this, increasing concentratio... |
The accumulation of delta-aminolevulinic acid (ALA) was studied in greening maize (Zea mays) leaves which were transferred to darkness and reilluminated after various periods of time. The system synthesizing ALA decays in the dark with a half-life of about 80 minutes. The onset of enzyme decay after transfer to darknes... |
The loss of microsomal NADH-cytochrome c reductase activity (EC 1.6.99.3) in cotyledons, known to accompany germination of Phaseolus vulgaris and thought to reflect the progress of cytoplasmic membrane senescence, can be simulated in an in vitro system in which isolated microsomes from 2-day-old tissue are treated with... |
Soybean (Glycine max cv. Bragg) petiolar tissue containing translocated (14)C-sucrose was quick frozen, freeze-substituted in acetone or propylene oxide and embedded in Epon. This procedure allowed cytological observations on sieve elements whose functional condition could be verified by microautoradiography. Sieve ele... |
The levels of reducing and nonreducing sugars, starch, soluble protein, and selected enzymes involved in the metabolism of sucrose, glucose-1-P, and glucose nucleotides were assayed in dehulled developing rice grains (Oryza sativa L. line IR1541-76-3) during the first 3 weeks after flowering. The level of reducing suga... |
The optimum temperature of protein synthesis in wheat seedlings (Triticum aestivum L.), measured as (14)C-leucine incorporation, depends on the growing temperature. Plants grown at reduced temperature (4 C) reach their optimum at 27.5 C, whereas plants kept at 36 C have the highest rate of protein synthesis at 35 C. Th... |
Dark-grown Euglena gracilis Klebs strain Z Pringsheim cells, which have been partially regreened in the light, show a striking, continued synthesis of the chloroplast enzyme ribulose 1,5-diphosphate carboxylase on transfer back into darkness. This dark synthesis of the enzyme was completely prevented by the addition of... |
Pyruvate orthophosphate dikinase was detected from Kalanchoë daigremontiana Hamet. et. Perr., a succulent plant with crassulacean acid metabolism. Enzyme activity was similar to that of maize extracts. Two enzymes demonstrating pyruvate orthophosphate dikinase activity from K. daigremontiana and Zea mays were found to ... |
The results of molecular weight studies, structural analysis of the [(14)C]polysaccharides, and enzymic properties indicate that the Pisum sativum guanosine diphosphosphate glucose: glucosyltransferase is an enzymic component involved in the biosynthesis of glucomannan chains. The properties of the Pisum sativum partic... |
Protein synthesis has been implicated in the cold-hardening process. Ribosomes from cold hardy and nonhardy black locust (Robinia pseudoacacia L.) seedlings were compared to determine if cold acclimation is related to alteration of ribosomal structure. Ribosomal structure, as indicated by thermal melting profiles, appe... |
The Km(CO(2)) values of ribulose 1,5-diphosphate carboxylase in freshly ruptured spinach (Spinacia oleracea L.) chloroplasts and in the purified form isolated from spinach leaves were found to be pH dependent. Raising the pH of the assay solution produced a substantial decrease in the Km(CO(2)) of both enzyme systems. ... |
Ornithine transcarbamoylase (carbamoyl phosphate:l-ornithine carbamoyltransferase, EC 2.1.3.3) has been partially purified from the blue-green alga Nostoc muscorum Kützing, an organism in which the enzyme seems to be involved in a bicarbonate-fixing pathway leading to citrulline. Pertinent to possible regulation of thi... |
In Zea mays L., addition of glucose to the induction medium has no effect on the induction of nitrate reductase during the initial 3 hours either in root tips (0-10 mm) or mature root sections (25-35 mm). With longer times, higher levels of enzyme activity are recovered from both root segments when glucose is present i... |
Biosynthesis of ent-kaurene was investigated in extracts of cell suspension cultures derived from tobacco callus (Nicotiana tabacum L.), tomato callus (Solanum lycopersicum L.), and in germinating tomato seeds. Incubation of extracts derived from the two cell cultures with either isopentenyl pyrophosphate-(14)C or with... |
The relationship of indoleacetic acid oxidase activity to peroxidase activity is complicated by numerous multiple forms of this enzyme system. It is not known if all isozymes of this complex system contain both types of activity. Isozyme analysis of commercial horseradish peroxidase and leaf extracts of yellow birch (B... |
The effect of temperature on respiration of mitochondria and tissue segments from three wheat (Triticum aestivum L.) and one rye (Secale cereale L.) cultivar grown at 2 and 24 C has been examined. Discontinuities in Arrhenius plots of respiratory activity against temperature were observed for mitochondria and tissue se... |
The cytochemical localizations of malate synthase (glyoxysomal marker) and glycolate oxidase (peroxisomal marker) have been examined in cotyledon segments and sucrose-gradient fractions from germinated cucumber (Cucumis sativus L.) seedlings. The seedlings were grown in the dark for 4 days, transferred to 4 hours of co... |
Growth-promoting action of simazine and other s-triazine herbicides was detected by the use of sorghum (Sorghum bicolor [L]. Moench) callus tissue and the chlorophyll retention test. Soil application of simazine [2-chloro-4, 6-bis(ethylamino)-s-triazine] at sublethal levels nearly doubled the growth-promoting action of... |
In etiolated pea (Pisum sativum L. cv. Alaska) shoots about 3% of the total extractable phytochrome was found in the mitochondrial fraction and about 4.5% in the microsomal fraction, while over 70% was soluble in the 105,000g supernatant. The value of Delta(DeltaA) per milligram of protein was significantly higher in t... |
As seeds of the French bean (Phaseolus vulgaris, L. cv. Tendergreen) mature, a single protein, G1 globulin (analogous to legumin), represents the majority of protein synthesized. Washed polysomes extracted from developing cotyledons had little endogenous activity in amino acid incorporation, but on addition of cell-fre... |
Electrophoretic analysis of the major seed protein, G1 globulin, from four strains of Phaseolus vulgaris L. revealed a three-banded pattern for two strains having a high methionine content (BBL 240 and PI 302,542). The other two strains (PI 207,227 and PI 229,815) known to have a lower seed methionine content, had a tw... |
myo-Inositol 1-phosphate synthase (EC 5.5.1.4) is the enzyme which catalyzes the synthesis of the precursor for the myo-inositol oxidation pathway. Rice callus grown in suspension culture provides a good source of plant enzyme. Use has been made of a noncompetitive inhibitor to prepare an affinity column for this enzym... |
Asparagine accounted for 50 to 70% of the nitrogen carried in translocatory channels serving fruit and seed of white lupin (Lupinus albus L.). Rates of supply of the amide always greatly exceeded its incorporation as such into protein. An asparaginase (l-asparagine amido hydrolase EC 3.5.1.1) was demonstrated in crude ... |
An attempt to isolate intact mitochondria from dry pea seeds (Pisum sativum var. Alaska) ended in failure. Cytochrome oxidase in crude mitochondrial fraction from dry seeds was separated into three fractions by sucrose density gradient centrifugation. Two of the fractions contained malate dehydrogenase, whereas the oth... |
Developmental and compartmentation studies were used to evaluate the relative roles of the oxidative pentose phosphate cycle, the Calvin cycle, and the glycolysis in cotyledons of radish (Raphanus sativus L.).Glucose-6-P dehydrogenase, 6-P-gluconate dehydrogenase, glucose-6-P isomerase, and the NAD-dependent glyceralde... |
Glutamate dehydrogenase becomes density labeled through the incorporation of deuterium and (15)N when detached oat leaves (Avena sativa var. Fulghum) are incubated in the presence of ammonia. The enzyme has been isolated by means of DEAE-cellulose chromatography, ammonium sulfate precipitation, isopycnic equilibrium ce... |
Anthranilate synthetase, phosphoribosyltransferase, phosphoribosyl anthranilate isomerase, and indoleglycerol phosphate synthetase were examined in partially purified extracts of the monocotyledon, Zea mays and the dicotyledon, Pisum sativum. The plant extracts were chromatographed on DEAE-cellulose and Sephadex G150. ... |
Carbamoyl phosphate synthetase of pea shoots (Pisum sativum L.) was purified 101-fold. Its stability was greatly increased by the addition of substrates and activators. The enzyme was strongly inhibited by micromolar amounts of UMP (Ki less than 2 mum). UDP, UTP, TMP, and ADP were also inhibitory. AMP caused either sli... |
Endogenous levels of cyclic adenosine-3':5'-monophosphate in coleoptile first leaf segments of oat (Avena sativa L.), potato (Solanum tuberosum L.) tubers, tobacco (Nicotiana tabacum L.) callus, and germinating seeds of lettuce (Lactuca sativa L.) were measured with a modified Gilman binding assay and a protein kinase ... |
Intact chloroplasts of spinach (Spinacia oleracea L.), sunflower (Helianthus annuus L.), and maize (Zea mays L.) mesophyll cells contained 0.33, 0.50, and 0.14% of bound hexosamine on a protein basis, respectively. Undifferentiated maize chloroplasts contained 0.19%. Values for chloroplast lamellae were, respectively, ... |
The influence of protein synthesis and nitrate reductase activity on nitrate absorption by barley (Hordeum vulgare L.) was investigated. Cycloheximide decreased nitrate absorption. Pretreatment studies showed that cycloheximide affects either energy transfer or nitrate reductase activity or both.Illumination increased ... |
Changes in ADP-glucose and UDP-glucose pyrophosphorylase activities were followed during tuber development of Solanum tuberosum and prolonged storage at 4 and 11 C. Potato tuberization was accompanied by a sharp increase in starch synthesis simultaneous with a marked rise in ADP-glucose pyrophosphorylase activity. When... |
A potato (Solanum tuberosum) phospholipid acyl-hydrolase, which - in the pH range 7.5 to 8.5-is at least 10,000 times more effective with phospholipids than with galactolipids, has been purified and characterized. It is a soluble enzyme readily distinguished from a neutral lipid lipase and a third lipid acyl-hydrolase ... |
Three distinct potato (Solanum tuberosum) lipid acyl-hydrolases have been isolated and characterized. Nonfluorescent esters of the fluorescent alcohols, N-methylindoxyl and N-methylumbelliferone, have been used as convenient substrates for lipid acyl-hydrolase estimation. Enzyme I has been shown to be a neutral lipase ... |
Results are reported which support the view that the photosynthetic photosystems are not involved in the high irradiance response (HIR) phenomenon of light-dependent anthocyanin biosynthesis in dark-grown Zea mays L. seedlings. A negative correlation between change in greening rates and change in light-dependent anthoc... |
The term "bound auxin" is herein used to describe auxin conjugates insoluble in organic solvents which dissolve indoleacetic acid (IAA) and its derivatives, but hydrolyzable by NaOH to release IAA. Bound auxin from pea stems was fractionated into water-soluble, water-insoluble/NaOH-hydrolyzable, and insoluble component... |
Isolated chloroplasts which have lost their envelopes and, in consequence, the soluble components which constitute the stroma, will nevertheless evolve O(2) when supplied with an artificial oxidant (the Hill reaction). They will also evolve O(2) with NADP as the Hill oxidant if supplemented with ferredoxin. With cataly... |
Inhibitor experiments indicate that photosynthetic electron transport is required for light activation of the pea (Pisum sativum) leaf chloroplast enzymes NADP-linked glyceraldehyde-3-phosphate dehydrogenase, NADP-linked malic dehydrogenase, ribulose-5-phosphate kinase and sedoheptulose-1,7-diphosphate phosphatase, and... |
The protein content of salt-washed cell walls isolated from etiolated stems of Pisum sativum L. approximately doubled during elongation. In the same period the concentration in the wall of hydroxyproline, hydrazine-labile (= presumably glycosylated) serine, valine, tyrosine, lysine, and histidine increased markedly in ... |
Growth of Alaska peas (Pisum sativum) is inhibited more than 60% by alpha-cyclopropyl-alpha-(p-methoxyphenyl)-5-pyrimidine methyl alcohol (ancymidol) treatment. This growth inhibition can be reversed completely by gibberellic acid application. Cell-free enzyme preparations from pea shoot tips and wild cucumber (Marah o... |
Oxygen inhibition of photosynthesis was studied with intact spinach (Spinacia oleracea L.) chloroplasts which exhibited very high rates of photosynthetic CO(2) reduction and were insensitive to additions of photosynthetic intermediates when CO(2) was available at saturating concentrations. Photosynthetic rates were mea... |
The amount of carbon (mumoles of carbon atoms) drained from the tricarboxylic acid cycle for protein synthesis was compared with mumoles of CO(2) released from the cycle at 2-day intervals during the growth of suspension cultures of Paul's Scarlet rose. We concluded that during the period of most rapid protein synthesi... |
A large amount of peroxide was found in twigs of poplar, Populus gelrica, which was grown in the field under natural conditions. The peroxide found in xylem and living bark was about 1.2 and 0.5 mumoles per gram dry weight sample, respectively, and served as a substrate both for catalase and cytochrome c peroxidase. |
NAD-specific "malic" enzyme (EC 1.1.1.39) has been isolated and purified 1200-fold from leaves of Kalanchoë daigremontiana. Kinetic studies of this enzyme, which is activated 14-fold by CoA, acetyl-CoA, and SO(4) (2-), suggest allosteric properties. Cofactor requirements show an absolute specificity for NAD and for Mn(... |
A membrane-associated 4-hydroxycinnamate hydroxylase (p-coumarate hydroxylase) from green leaves of Sorghum bicolor has been purified by mercaptoethanol treatment, ammonium sulfate fractionation, and chromatography on hydroxyapatite and agarose 1.5m. Ascorbate (or reduced pyridine nucleotide) is an obligatory electron ... |
A three-phase discontinuous sucrose gradient yielded two fractions of chloroplast envelope membranes from spinach (Spinacia oleracea L.), sunflower (Helianthus annuus L.), and maize (Zea mays L., mesophyll and undifferentiated chloroplasts). These species were selected to represent plants with fast photorespiration and... |
Energy charge [(ATP) + (1/2) (ADP)]/[(ATP) + (ADP) + (AMP)] and glutamine synthetase activity (transferase reaction) of roots increase in a near congruent manner when decotyledonized sunflower plants (Helianthus annuus L. var. Mammoth Russian) are grown in nitrate for 9 days. Replacement of nitrate with ammonium for th... |
The metabolic activity of individual lipid classes found in developing soybean cotyledons (Glycine max.) is estimated by determining the degradation rate of the compound under given conditions. Pulse-labeling and dual substrate labeling are used to evaluate this parameter. These studies indicate first order decay kinet... |
The organization of electron transport in photosystem II of spinach (Spinacia oleracea) chloroplasts was studied by means of various chelators and uncouplers. The partial reactions used included H(2)O-->methyl viologen, H(2)O-->silicomolybdic acid H(2)O-->ferricyanide, and H(2)O-->dimethylbenzoquinone. Three types of c... |
A comparison of mitochondria isolated from 2 and 24 C grown winter wheat (Triticum aestivum L.) and winter rye (Secale cereale L.) seedlings revealed no correlation between changes in swelling and contraction characteristics and extent of cold hardiness. The swelling response changed markedly due to growth at low tempe... |
The activity and extent of adenylylation of glutamine synthetase was examined in both free-living and bacteroid forms of Rhizobium japonicum in the presence of excess ammonia. Ammonia caused an apparent repression of glutamine synthetase in free-living R. japonicum and adenylylation of the enzyme was also increased. In... |
RNA species from the haploid gametophyte generation of the moss Tortula ruralis exhibit typical eukaryotic characteristics. The major ribosomal and soluble RNA species are stable during drying and rehydration. RNA synthesis occurs rapidly on reintroduction of the moss to water and incorporation into high molecular weig... |
Timing of protein synthesis which is a prerequisite to DNA synthesis induced in potato tuber tissue (Solanum tuberosum L.) by cut injury has been studied using cycloheximide. The induction of DNA synthesis which was measured by incorporation of (3)H-thymidine was completely inhibited when the inhibitor was applied to t... |
Potato mitochondria (Solanum tuberosum var. Russet Burbank), which readily phosphorylate ADP in oxidative phosphorylation, show low levels of ATPase activity which is stimulated neither by Mg(2+), 2,4-dinitrophenol, incubation with respiratory substrates, nor disruption by sonication or treatment with Triton X-100, ind... |
Ribulose 1,5-diphosphate (RuDP) carboxylase has been partially purified from dark-grown nonphotosynthetic endosperms of germinating castor beans (Ricinus communis var. Hale). The Km values for RuDP, HCO(3) (-), and Mg(2+) are 0.51, 33, and 1.78 mm, respectively. The pH optimum for the carboxylation reaction is pH 7.5. ... |
d(-)threo-Chloramphenicol blocks chlorophyll and plastid protein synthesis in Euglena. During chloroplast development in white light, but not in red, the cells escape from chloramphenicol inhibition and chlorophyll formation is restored. Concomitantly, chloramphenicol is reduced. Reduction of chloramphenicol in an enzy... |
Illuminated pea (Pisum sativum) chloroplasts can convert glutamate to glutamine using ATP generated by photophosphorylation to drive the glutamine-synthetase reaction. Light-dependent glutamine synthesis is sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU), but only at concentrations higher than are necessar... |
This work supports further the thesis that under conditions of water stress, cell water content may supersede hormonal regulation in effecting enzyme activity, thus becoming a regulatory factor in cellular metabolism. Addition of NaCl to the root medium of barley plants (Hordeum vulgare L.) markedly increased leaf RNas... |
Upon dehardening of stem bark of black locust (Robinia pseudoacacia), a significant decrease in phospholipid content on a milligram protein basis was observed in various crude particulate cell fractions. To ascertain this with a defined membrane, microsomal preparations were separated into several membrane fractions on... |
The influence of ionic composition and pH of extractant on the relationship between the extracted proteins and the cold tolerance of Vernal and Arizona Common alfalfa (Medicago sativa L.) was examined. Five environments were used to induce different tolerance levels. The quantity of protein extracted from plants was in... |
The soluble proteins of C(3) and C(4) mesophyll chloroplasts and C(4) bundle sheath extracts have been analyzed by gel electrophoresis for fraction I protein. Gel scans of soluble protein from C(4) bundle sheath extracts and C(3) mesophyll chloroplasts showed typical fraction I protein peaks that could be identified by... |
Undegraded free and membrane-bound polysomes were isolated from developing kernels of Zea mays L. frozen in liquid nitrogen. Freezing in liquid nitrogen was a prerequisite for preserving polysome structure in stored kernels. Membrane-bound polysomes from 22-day post-pollination kernels ground in high pH buffers contain... |
Chloroplast and photosystem I particles were encapsulated in small spheres (about 20 mum diameter) with an artificial membrane built up by cross-linking amino groups of protamine with toluenediisocyanate. The artificial membrane was permeable to small substrate and product molecules but not to soluble proteins. Photosy... |
The structures of the four wall-released elicitor fractions isolated from the Phytophthora megasperma var. sojae mycelial walls have been examined. The results demonstrate that fraction I is primarily composed of a branched beta-1,3-glucan, similar in structure to the extracellular elicitors described previously (Ayers... |
Lipoxygenase (EC 1.13.1.13) was found in seedlings of Citrullus lanatus (Thunb.) Matsum. and Nakai (watermelon). The enzyme has pH optima of 4.4 and 5.5 and is inhibited by 0.2 mM nordihydroguaiaretic acid. It is present in two functional units with estimated molecular weights of 120,000 and 240,000, respectively.A new... |
Growth of the fungus Helminthosporium maydis race T in a basal glucose-l-asparagine liquid medium, pH 5, is inhibited by thiamine-HCl. Analysis of the media for organic acids reveals that the extracellular pyruvate concentration decreases as the thiamine-HCl concentration of the medium increases. Extracellular ethanol,... |
Glutamate synthetase (glutamine[amide]:alpha ketoglutarate amino transferase oxidoreductase) activity has been demonstrated in the developing cotyledons of Pisum sativum L. cv. Burpeeana. The enzyme appears to be soluble and is specific for glutamine as amide donor. The enzyme activity is greater with NADH than with NA... |
A peptidase hydrolyzing the dipeptide Ala-Gly optimally at pH 8 to 9 was purified about 3500-fold from germinated grains of barley (Hordeum vulgare L.). According to disc electrophoresis in the presence of sodium dodecyl sulfate, the preparation was about 90% pure.The enzyme preparation hydrolyzed all of the 15 neutral... |
Intercellular distribution of enzymes involved in amino nitrogen synthesis was studied in leaves of species representing three C(4) groups, i.e. Sorghum bicolor, Zea mays, Digitaria sanguinalis (NADP malic enzyme type); Panicum miliaceum (NAD malic enzyme type); and Panicum maximum (phosphoenolpyruvate carboxykinase ty... |
The effect of protein additives on acetylene reduction (N(2) fixation) by Rhizobium associated with soybean cells (Glycine max [L.] Merr.) in vitro was studied. Acetylene reduction was promoted on the basal medium supplemented with 1.4 mg of N/ml supplied as aqueous extracts of hexane-extracted soybean, red kidney bean... |
Phosphoenolpyruvate carboxylase has been purified to homogeneity from maize (Zea mays L. var. Golden Cross Bantam T51) leaves. The ratio of specific activities in crude extracts and the purified enzyme suggests that the enzyme is a major soluble protein in the tissue. The enzyme has a sedimentation coefficient (s(20,w)... |
Lignin content and enzymes involved in lignification were measured in leaf discs of reed canarygrass (Phalaris arundinacea L.) inoculated with Helminthosporium avenae and floated on water or solutions of cycloheximide (25 mug/ml). Fungal germ tubes did not penetrate localized lignified swellings, which formed beneath p... |
The effects of nitrogen source NO(3) (-) or NH(4) (+) on nitrogen metabolism during the first 2 weeks of germination of the rice seedling (Oryza sativa L., var. IR22) grown in nutrient solution containing 40 mug/ml N were studied. Total, soluble protein, and free amino N levels were higher in the NH(4) (+)-grown seedli... |
Germination of mung beans (Phaseolus aureus, Roxb.) is accompanied by an increase in the activity of the endopeptidase involved in storage protein metabolism. Enzyme activity in the cotyledons increases 25-fold during the first 5 days of germination. The cotyledons also contain inhibitory activity against the endopepti... |
The effect of various day temperatures on NADH-nitrate reductase, NADH- and NADPH-glutamate dehydrogenases, nitrate, protein and leaf area, measured at intervals during the ontogeny of the first trifoliolate soybean leaf, was determined. At 32.5 C and 25 C, nitrate concentration, nitrate reductase, and NADPH-glutamate ... |
Reserve carbohydrates were determined on developing endosperm of a new line of sugary maize (Zea mays L.). Other entries, included for comparative purposes, were Midway (sugary), Funks G4646 (starchy), and Illini X-tra Sweet (shrunken-2). Sucrose in the new line, Illinois 677a, was more than twice that of Midway at mos... |
The enzymic nature of the protein moiety of protochlorophyll(ide) holochrome was studied by following the fate of the [(14)C]protochlorophyll(ide) formed when dark-grown barley (Hordeum vulgare) or bean (Phaseolus vulgaris) leaves are incubated in the dark with 3 mm 4-delta-[(14)C]aminolevulinic acid. It was found that... |
When sweet potato (Ipomoea batatas) root tissue was infected by Ceratocystis fimbriata, activity of the enzyme system from mevalonate to isopentenyl pyrophosphate, especially of pyrophosphomevalonate decarboxylase (EC 4.1.1.33), was increased in the noninfected tissue adjacent to the infected region, preceding the fura... |
Germinating cotton (Gossypium hirsutum L. cv. Deltapine 16) cotyledons developed two peaks of in vitro nitrate reductase activity; the first was stable in vitro and appeared 24 hours after imbibition; and the second, which was extremely labile in vitro, began to develop after the seedlings had emerged and developed chl... |
Light inactivation of glucose-6-phosphate dehydrogenase within the pea (Pisum sativum L.) leaf chloroplast has a narrow pH optimum between 7.2 and 7.4 and is NADP-sensitive. The pH optimum for dark activation is slightly lower. Inactivation apparently results in a simple decrease in maximal velocity of the chloroplasti... |
Aging of slices of potato tuber (Solanum tuberosum L.) in an aerated liquid medium induces a number of changes in mitochondrial activities. A nonphosphorylative, cyanide-insensitive electron transport pathway (alternate pathway) is brought into operation. The rate of oxidation of exogenous NADH increases markedly and t... |
During the transition from photoheterotrophic growth on acetate to phototrophic growth on carbon dioxide, there is a decrease in isocitrate lyase and increase in ribulose-1,5-diphosphate carboxylase activity in Chlamydobotrys stellata cultures. The increase in ribulose-1,5-diphosphate carboxylase activity is the result... |
Palisade parenchyma cells and spongy parenchyma cells were isolated separately from Vicia faba L. leaflets. Extracts of the cell isolates were assayed for several enzymes involved in CO(2) fixation and photorespiration. When compared on a chlorophyll basis, the levels of enzyme activities either were equal in the diffe... |
Glycolate dehydrogenase activity was detected in cell-free extracts of Oscillatoria sp. prepared by osmotic lysis of spheroplasts in 0.05 m potassium phosphate buffer, pH 7.5, containing 0.3 m mannitol. Most of the enzyme activity was found in a particulate fraction and localized in the photosynthetic lamellae after ce... |
Aspartate transcarbamylase (ATCase) activity declines in etiolated cowpea (Vigna unguiculata L. Walp.) and soybean (Glycine max L. Merr.) hypocotyls between 3 and 11 days after planting. Treating cow-pea hypocotyls with cycloheximide (CH), actinomycin D (AMD), 6-methyl purine (6-MP), or cordycepin increases ATCase acti... |
A new method is described for studying the metabolism of air-dry seeds. An initial pulse of (14)CO(2) was supplied to seeds maintained in air at controlled low water potentials for 6 months. Seeds were also infiltrated with 2-(14)C-acetate and with (14)C-l-leucine at 0 C, redried rapidly at 0 C, and maintained at contr... |
An l-cysteinyl-tRNA synthetase (EC 6.1.1.16) from Phaseolus aureus has been purified approximately 200-fold. The enzyme uses selenocysteine as substrate in the ATP-PPi exchange assay; other cysteine analogs were inactive. The molecular weight as determined by Sephadex G-200 column chromatography is about 61,000; sodium... |
The major globulin of the French bean (Phaseolus vulgaris L.) undergoes a reversible pH-dependent polymerization. At pH values above 6.5, the monomeric form of the protein predominates; and at pH values below 6.5, the protein occurs as a polymer, probably a tetramer. At extremes of pH, the protein dissociates further i... |
NADP-dependent glutamate dehydrogenase was partially purified from extracts of the marine siphonous green alga Caulerpa simpliciuscula. The enzyme had an apparent Km NH(4) (+) of 0.4 to 0.7 mm and was highly specific for NADPH, alpha-ketoglutarate, and ammonium ions.The bulk of the NADP-glutamate dehydrogenase was isol... |
By use of affinity chromatography on blue dextran-Sepharose, two nitrate reductases from rice (Oryza sativa L.) seedlings, specifically, NADH:nitrate oxidoreductase (EC 1.6.6.1) and NAD(P)-H:nitrate oxidoreductase (EC 1.6.6.2), have been partially separated. Nitrate-induced seedlings contained more NADH-nitrate reducta... |
Osmotic regulation in the flagellate Ochromonas malhamensis Pringsheim is mainly mediated by fluctuations in the pool size of alpha-galactosyl-(1-->1)-glycerol (isofloridoside). A regulated key enzyme of isofloridoside metabolism is the galactosyl transferase producing isofloridoside phosphate. The activity of this enz... |
Freshly prepared spinach leaf protoplasts were gently ruptured by mechanical shearing followed by sucrose density gradient centrifugation to separate constituent cell organelles. The isolation of intact Class I chloroplasts (d = 1.21) in high yield, well separated from peroxisomes and mitochondria, was evidenced by the... |
Cultured soybean (Glycine max, Kanrich variety) cells grow with 25 mm urea as the sole nitrogen source but at a slower rate than with the Murashige and Skoog (MS) (Physiol. Plant. 15: 473-497, 1962) nitrogen source of 18.8 mm KNO(3) and 20.6 mm NH(4)NO(3). Growth with urea is restricted by 18.8 mm NO(3) (-), 50 mm meth... |
The cell walls of barley (Hordeum vulgare var. Himalaya) aleurone layers undergo extensive degradation during the tissue's response to gibberellic acid. Previous work had shown that these cell walls consist almost entirely of arabinoxylan. In this study we show that gibberellic acid stimulates endo-beta-1,4-xylanase ac... |
NADP- and NAD-dependent glucose dehydrogenase was partially purified from a dark-grown blue-green alga (endophytic Nostoc strain MAC). Polyacrylamide gel electrophoresis established that a single protein possessed dual activity for either NADP or NAD. No other electron acceptor substituted for pyridine nucleotides and ... |
Barley (Hordeum vulgare L. var. Prior) leaves converted more (14)C-glutamic acid to free proline when water-stressed than when turgid; neither decreased protein synthesis nor isotope trapping by the enlarged free proline pools found in wilted tissue seemed to account for the result. This apparent stimulation of proline... |
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