Publications

pathways of fatty acid hydroperoxide metabolism in spinach leaf chloroplasts.	the metabolism of 13-hydroperoxylinolenic acid was examined in protoplasts and homogenates prepared from mature leaves of spinach (spinacia oleracea l.). chloroplast membranes were the principal site for metabolism of the compound by at least two highly hydrophobic enzyme systems, hydroperoxide lyase and hydroperoxide dehydrase, the new name for an enzyme system formerly known as hydroperoxide isomerase and hydroperoxide cyclase. hydroperoxide lyase was most active above ph 7 and could be separa ...	1987	16665806
choline oxidation by intact spinach chloroplasts.	plants synthesize betaine by a two-step oxidation of choline (choline --> betaine aldehyde --> betaine). protoplast-derived chloroplasts of spinach (spinacia oleracea l.) carry out both reactions, more rapidly in light than in darkness (ad hanson et al. 1985 proc natl acad sci usa 82: 3678-3682). we investigated the light-stimulated oxidation of choline, using spinach chloroplasts isolated directly from leaves. the rates of choline oxidation obtained (dark and light rates: 10-50 and 100-300 nano ...	1988	16665893
dihydroxyacetone phosphate reductase in plants.	two forms of dihydroxyacetone phosphate reductase are present in spinach, soybean, pea, and mesophyll cells of corn leaves. an improved homogenizing medium was developed to measure this activity. the enzyme was detectable only after dialysis of the 35 to 70% saturated (nh(4))(2)so(4) fraction and the two forms were separated by chromatography on either deae cellulose or sephacryl s-200. about 80% of the reductase was one form in the chloroplast and the rest was a second form in the cytosol as de ...	1988	16665901
stromal free calcium concentration and light-mediated activation of chloroplast fructose-1,6-bisphosphatase.	light-mediated activation of fructose-1,6-bisphosphatase (ec 3.1.3.11) in intact spinach chloroplasts (spinacia oleracea l.) is enhanced in the presence of 10(-5) molar external free ca(2+). the most pronounced effect is observed during the first minutes of illumination. ruthenium red, an inhibitor of light-induced ca(2+) influx, inhibits this ca(2+) stimulated activation. in isolated stromal preparations, the activation of fructose-1,6-bisphosphatase is already enhanced by 2 minutes of exposure ...	1988	16665924
comparison of starch and adp-glucose pyrophosphorylase levels in nonembryogenic cells and developing embryos from induced carrot cultures.	cultures of carrot (daucus carota l.) in a medium without added 2,4-dichlorophenoxyacetic acid were separated into fractions of embryos at different stages of development (large globular and heart, torpedo, and germinating) and nonembryogenic cells. the average starch content per cell in these fractions was similar. however, due to the smaller sizes of the cells of the embryos relative to the nonembryogenic cells, starch content per weight of tissue was higher in the embryos. the adp-glucose pyr ...	1988	16665929
characterization of the rna required for biosynthesis of delta-aminolevulinic acid from glutamate : purification by anticodon-based affinity chromatography and determination that the uuc glutamate anticodon is a general requirement for function in ala biosynthesis.	the heme and chlorophyll precursor delta-aminolevulinic acid acid (ala) is formed in plants and algae from glutamate in a process that requires at least three enzyme components plus a low molecular weight rna which co-purifies with the trna fraction during deae-cellulose column chromatography. rna that is effective in the in vitro ala biosynthetic system was extracted from several plant and algal species that form ala via this route. in all cases, the effective rna contained the uuc glutamate an ...	1988	16665935
synthesis of mono- and digalactosyldiacylglycerol in isolated spinach chloroplasts.	purified, intact chloroplasts of spinacia oleracea l. synthesize galactose-labeled mono- and digalactosyldiacylglycerol (mgdg and dgdg) from udp-[u-(14)c]galactose. in the presence of high concentrations of unchelated divalent cations they also synthesize tri- and tetra-galactosyldiacylglycerol. the acyl chains of galactose-labeled mgdg are strongly desaturated and such mgdg is a good precursor for dgdg and higher oligogalactolipids. the synthesis of mgdg is catalyzed by udp-gal:sn-1,2-diacylgly ...	1988	16666019
gradients of intercellular co(2) levels across the leaf mesophyll.	most current photosynthesis models, and interpretations of many wholeleaf co(2) gas exchange measurements, are based on the often unstated assumption that the partial pressure of co(2) is nearly uniform throughout the airspaces of the leaf mesophyll. here we present measurements of co(2) gradients across amphistomatous leaves allowed to assimilate co(2) through only one surface, thus simulating hypostomatous leaves. we studied five species: eucalyptus pauciflora sieb. ex spreng., brassica chinen ...	1988	16666027
isolation and characterization of a starchless mutant of arabidopsis thaliana (l.) heynh lacking adpglucose pyrophosphorylase activity.	a mutant of arabidopsis thaliana lacking adpglucose pyrophosphorylase activity (ec 2.7.7.27) was isolated (from a mutagenized population of plants) by screening for the absence of leaf starch. the mutant grows as vigorously as the wild type in continuous light but more slowly than the wild type in a 12 hours light/12 hours dark photoperiod. genetic analysis showed that the deficiency of both starch and adpglucose pyrophosphorylase activity were attributable to a single, nuclear, recessive mutati ...	1988	16666044
specific labeling of the phosphate translocator in c(3) and c(4) mesophyll chloroplasts by tritiated dihydro-dids (1,2-ditritio-1,2-[2,2' -disulfo-4,4' -diisothiocyano] diphenylethane).	the phosphate translocator protein of c(3) and c(4) mesophyll chloroplast envelopes was specifically labeled using the anion exchange inhibitor, 1,2-ditritio-1,2-(2,2' -disulfo-4,4' -diisothiocyano) diphenylethane ([(3)h](2)-dids). intact mesophyll chloroplasts were isolated from the c(3) plants, spinacia oleracea l. (spinach) and pisum sativum l. (pea), and the c(4) plant, zea mays l. (corn). chloroplasts were incubated with 5 to 50 mum [(3)h](2)-dids and, in addition, pea chloroplasts were als ...	1988	16666053
measurement of proton-linked transport activities in pyranine loaded chloroplast inner envelope vesicles.	a method has been devised for loading chloroplast inner envelope vesicles prepared from pea (pisum sativum l. var progress no. 9) or spinach (spinacia oleracea l.) with 8-hydroxypyrene-1,3,6-trisulfonate (pyranine), a membrane impermeant, fluorescent ph indicator. two known proton-linked transport activities of the inner envelope, glycolate/h(+) co-transport and phosphate/phosphoglycerate exchange have been shown to cause quenching of the internal pyranine fluorescence. this represents the first ...	1988	16666080
spectral, photophysical, and stability properties of isolated photosystem ii reaction center.	photosystem ii reaction center (rc) preparations isolated from spinach (spinacea oleracea) by the nanba-satoh procedure (o nanba, k satoh 1987 proc natl acad sci usa 84: 109-112) are quite labile, even at 4 degrees c in the dark. simple spectroscopic criteria were developed to characterize the native state of the material. degradation of the rc results in (a) blue-shifting of the red-most absorption maximum, (b) a shift of the 77 k fluorescence maximum from approximately 682 nm to approximately ...	1988	16666138
differential inhibition and activation of two leaf dihydroxyacetone phosphate reductases : role of fructose 2,6-bisphosphate.	the chloroplastic and cytosolic forms of spinach (spinacia oleracea cv long standing bloomsdale) leaf nadh:dihydroxyacetone phosphate (dhap) reductase were separated and partially purified. the chloroplastic form was stimulated by dithiothreitol, reduced thioredoxin, dihydrolipoic acid, 6-phosphogluconate, and phosphate; the cytosolic isozyme was stimulated by fructose 2,6-bisphosphate but not by reduced thioredoxin. end product components that severely inhibited both forms of the reductase incl ...	1988	16666150
regulation of ribulose-1,5-bisphosphate carboxylase activity by the activase system in lysed spinach chloroplasts.	ribulose-1,5-bisphosphate (rubp) carboxylase in lysed spinach (spinacia oleracea l. cv virtuosa) chloroplasts that had been partly inactivated at low co(2) and mg(2+) by incubating in darkness with 4 millimolar partially purified rubp was reactivated by light. if purified rubp was used to inhibit dark activation of the enzyme, reactivation by light was not observed unless fructose-1,6-bisphosphate, atp, or adp plus inorganic phosphate were also added. presumably, adp plus inorganic phosphate act ...	1988	16666184
ion homeostasis in chloroplasts under salinity and mineral deficiency : i. solute concentrations in leaves and chloroplasts from spinach plants under nacl or nano(3) salinity.	spinach (spinacia oleracea var "yates") plants in hydroponic culture were exposed to stepwise increased concentrations of nacl or nano(3) up to a final concentration of 300 millimoles per liter, at constant ca(2+)-concentration. leaf cell sap and extracts from aqueously isolated spinach chloroplasts were analyzed for mineral cations, anions, amino acids, sugars, and quarternary ammonium compounds. total osmolality of leaf sap and photosynthetic capacity of leaves were also measured. for comparis ...	1988	16666232
ion homeostasis in chloroplasts under salinity and mineral deficiency: ii. solute distribution between chloroplasts and extrachloroplastic space under excess or deficiency of sulfate, phosphate, or magnesium.	spinach (spinacia oleracea var "yates") plants grown hydroponically were exposed to an excess or deficiency of various mineral ions. solutes were measured in leaf extracts and in isolated intact chloroplasts. under phosphate (120 millimoles per liter nah(2) po(4)), sulfate (200 millimolar per liter (na(2) so(4)), or magnesium excess (150 millimolar per liter mgcl(2)), concentrations of these ions in leaf extracts increased, but in chloroplasts, concentrations of all ions remained constant. conce ...	1988	16666233
catalysis of ribulosebisphosphate carboxylase/oxygenase activation by the product of a rubisco activase cdna clone expressed in escherichia coli.	ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) activase activity was obtained from a partially purified extract of escherichia coli transformed with a 1.6-kilobase spinach (spinacia oleracea l.) cdna clone. this activity was atp-dependent. catalysis of rubisco activation by spinach and cloned rubisco activase was accompanied by the same extent of carboxyarabinitol bisphosphate-trapped (14)co(2) as occurred in spontaneous activation, indicating that rubisco carbamylation is one facet o ...	1988	16666245
chloroplast osmotic adjustment and water stress effects on photosynthesis.	previous studies have suggested that chloroplast stromal volume reduction may mediate the inhibition of photosynthesis under water stress. in this study, the effects of spinach (spinacia oleracea, var ;winter bloomsdale') plant water deficits on chloroplast photosynthetic capacity, solute concentrations in chloroplasts, and chloroplast volume were studied. in situ (gas exchange) and in vitro measurements indicated that chloroplast photosynthetic capacity was maintained during initial leaf water ...	1988	16666266
effects of temperature pretreatment in the dark on photosynthesis of the intact spinach chloroplast.	isolated, intact spinach (spinacia oleracea l. var. "long standing bloomsdale") chloroplasts were heated in the dark and the effect of this treatment on photosynthetic activities was determined at 25 degrees c. dark incubation of the chloroplasts for 10 minutes at 35 degrees c and ph 8.1 resulted in a 50% decline in co(2) photoassimilation. this decline in photosynthetic performance was dependent upon time, temperature, and medium ph with the optimum effect at acidic ph values. photosynthetic de ...	1988	16666267
oxygen-18 and deuterium labeling studies of choline oxidation by spinach and sugar beet.	chenopods synthesize betaine by a two-step oxidation of choline: choline --> betaine aldehyde --> betaine. the pathway is chloroplastic; the first step has been shown in isolated spinach (spinacia oleracea l.) chloroplasts to be o(2)- and light-dependent, the role of light being to provide reducing power (p weigel, ea weretilnyk, ad hanson 1988 plant physiol 86: 54-60). here, we report use of in vivo(18)o- and (2)h-labeling in conjunction with fast atom bombardment mass spectrometry to test for ...	1988	16666370
preparation and characterization of envelope membranes from nongreen plastids.	we have developed a reliable procedure for the purification of envelope membranes from cauliflower (brassica oleracea l.) bud plastids and sycamore (acer pseudoplatanus l.) cell amyloplasts. after disruption of purified intact plastids, separation of envelope membranes was achieved by centrifugation on a linear sucrose gradient. a membrane fraction, having a density of 1.122 grams per cubic centimeter and containing carotenoids, was identified as the plastid envelope by the presence of monogalac ...	1988	16666372
ferredoxin cross-links to a 22 kd subunit of photosystem i.	we have used a cross-linking approach to study the interaction of ferredoxin (fd) with photosystem i (psi). the cross-linking reagent n-ethyl-3-(3-dimethylaminopropyl) carbodiimide was found to cross-link spinach fd to a 22 kilodalton subunit of psi in both isolated spinach (spinacia oleracea) psi complexes and spinach thylakoid membranes. the product had an apparent molecular weight of 38 kilodaltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was identified as a cross-link ...	1988	16666389
effects of irradiance and methyl viologen treatment on atp, adp, and activation of ribulose bisphosphate carboxylase in spinach leaves.	since activation of ribulose bisphosphate carboxylase (rubisco) by rubisco activase is sensitive to atp and adp in vitro, we aimed to test the correlation between atp level and rubisco activation state in intact leaves of spinacia oleracea l. in response to changes in irradiance and after feeding the electron acceptor methyl viologen. leaves were exposed to various irradiances for 45 minutes at atmospheric partial pressures of co(2) and o(2). after measuring the rate of co(2) assimilation, leave ...	1988	16666396
isolation of dihydroxyacetone phosphate reductase from dunaliella chloroplasts and comparison with isozymes from spinach leaves.	a dihydroxyacetone phosphate (dhap) reductase has been isolated in 50% yield from dunaliella tertiolecta by rapid chromatography on diethylaminoethyl cellulose. the activity was located in the chloroplasts. the enzyme was cold labile, but if stored with 2 molar glycerol, most of the activity was restored at 30 degrees c after 20 minutes. the spinach (spinacia oleracea l.) reductase isoforms were not activated by heat treatment. whereas the spinach chloroplast dhap reductase isoform was stimulate ...	1988	16666401
purification and assay of rubisco activase from leaves.	ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) activase protein was purified from spinach leaves by ammonium sulfate precipitation and ion exchange fast protein liquid chromatography. this resulted in 48-fold purification with 70% recovery of activity and yielded up to 18 milligrams of rubisco activase protein from 100 grams of leaves. based on these figures, the protein comprised approximately 2% by weight of soluble protein in spinach (spinacia oleracea l.) leaves. the preparations ...	1988	16666412
glutamine transport and the role of the glutamine translocator in chloroplasts.	the transport of l-[(14)c]glutamine in oat (avena sativa l.) and spinach (spinacia oleracea l.) chloroplasts was studied by a conventional single-layer and a newly developed stable double-layer silicone oil filtering system. [(14)c]glutamine was actively transported into oat chloroplasts against a concentration gradient. metabolite uptake was greatly affected by the endogenous dicarboxylate pools, which could be easily changed by preloading the chloroplast with specific exogenous substrate. glut ...	1988	16666419
carbon dioxide-induced oscillations in fluorescence and photosynthesis: role of thylakoid membrane energization in regulation of photosystem ii activity.	the response of co(2) fixation to a sudden increase in ambient co(2) concentration has been investigated in intact leaf tissue from spinach (spinacia oleracea) using a dual channel infrared gas analyzer. simultaneous with these measurements, changes in fluorescence emission associated with a weak, modulated measuring beam were recorded. application of brief (2-3 seconds) dark intervals enabled estimation of the dark fluorescence level (f(o)) under both steady state and transient conditions. the ...	1988	16666432
a starch deficient mutant of arabidopsis thaliana with low adpglucose pyrophosphorylase activity lacks one of the two subunits of the enzyme.	a starch deficient mutant of arabidopsis thaliana (l.) heynh. has been isolated in which leaf extracts contain only about 5% as much activity of adpglucose pyrophosphorylase (ec 2.7.7.27) as the wild type. a single, nuclear mutation at a previously undescribed locus designated adg2 is responsible for the mutant phenotype. although the mutant contained only 5% as much adpglucose pyrophosphorylase activity as the wild type, it accumulated 40% as much starch when grown in a 12 hour photoperiod. the ...	1988	16666440
characterization of elemental sulfur in isolated intact spinach chloroplasts.	incubation of intact spinach (spinacia oleracea l.) chloroplasts in the presence of (35)so(4) (2-) resulted in the light-dependent formation of a chloroform-soluble sulfur-containing compound distinct from sulfolipid. we have identified this compound as the most stable form (s(8)) of elemental sulfur (s(0), valence state for s = o) by mass spectrometry. it is possible that elemental sulfur (s(0)) was formed by oxidation of bound sulfide, i.e. after the photoreduction of sulfate to sulfide by int ...	1988	16666485
evidence from solanum tuberosum in support of the dual-pathway hypothesis of aromatic biosynthesis.	key branchpoint enzymes of aromatic amino acid biosynthesis, 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (ds) and chorismate mutase (cm), have previously been shown to exist as separate compartmentalized isozymes in the chloroplasts and cytosol of tobacco, sorghum and spinach. although additional examples of plants containing these isozyme pairs are accumulating, some studies in the literature report the presence of only the single plastidic ds or cm enzyme. such apparent exceptions con ...	1989	16666497
light-dependent kinetics of 2-carboxyarabinitol 1-phosphate metabolism and ribulose-1,5-bisphosphate carboxylase activity in vivo.	the light-dependent kinetics of the apparent in vivo synthesis and degradation of 2-carboxyarabinitol 1-phosphate (ca1p) were studied in three species of higher plants which differ in the extent to which this compound is involved in the light-dependent regulation of ribulose-1,5-bisphosphate carboxylase (rubisco) activity. detailed studies with phaseolus vulgaris indicate that both the degradation and synthesis of this compound are light-stimulated, although light is absolutely required only for ...	1989	16666511
changes in the activity of the chloroplastic and cytosolic forms of dihydroxyacetone phosphate reductase during maturation of leaves.	young or mature rosette leaves from spinach (spinacia oleracea l.) plants growing in the field, in the greenhouse, or in a growth chamber under a regimen of 8 hours light and 16 hours dark contained 15 to 50 nanomoles per minute per gram wet weight of nadh:dihydroxyacetone phosphate reductase activity. of this activity, 75 to 87% was the chloroplastic isoform and 25 to 13% was the cytosolic form. when plants were induced to senesce, as measured by stem elongation and flowering, the percentage of ...	1989	16666531
the association of d-ribulose- 1,5-bisphosphate carboxylase/oxygenase with phosphoribulokinase.	when ribulose- 1,5-bisphosphate carboxylase/oxygenase was purified from spinach leaves (spinacia oleracea) using precipitation with polyethylene glycol and mgcl(2) followed by deae cellulose chromatography, 75% of phosphoribulokinase and 7% of phosphoriboisomerase activities copurified with ribulose- 1,5-bisphosphate carboxylase/oxygenase. this enzyme preparation showed ribose-5-phosphate and ribulose-5-phosphate dependent carboxylase and oxygenase activities which were nearly equivalent to its ...	1989	16666540
freezing tolerance of citrus, spinach, and petunia leaf tissue : osmotic adjustment and sensitivity to freeze induced cellular dehydration.	seasonal variations in freezing tolerance, water content, water and osmotic potential, and levels of soluble sugars of leaves of field-grown valencia orange (citrus sinensis) trees were studied to determine the ability of citrus trees to cold acclimate under natural conditions. controlled environmental studies of young potted citrus trees, spinach (spinacia pleracea), and petunia (petunia hybrids) were carried out to study the water relations during cold acclimation under less variable condition ...	1989	16666563
purification and preliminary characterization of sucrose-phosphate synthase using monoclonal antibodies.	monoclonal antibodies specific for sucrose phosphate synthase (sps; ec 2.4.1.14) have been obtained for the first time. three independent clones have been isolated which inhibited spinach (spinacia oleracea l.) leaf sps activity and facilitated the enzyme purification by immunoprecipitation. all three clones were specific for the spinach enzyme but neither inhibited nor precipitated the sps present in tissue extracts of maize (zea mays l.), barley (hordeum vulgare l.), soybean (glycine max l.), ...	1989	16666575
evidence for a light dependent increase of phosphoglucomutase activity in isolated, intact spinach chloroplasts.	phosphoglucomutase (pgm) activity was measured in spinach (spinacia oleracea l.) chloroplasts. initial enzyme activity in a chloroplast lysate was 5 to 10% of total activity measured with 1 micromolar glucose 1,6-bisphosphate (glc 1,6-p(2)) in the assay. initial pgm activity increased 2- to 3-fold when chloroplasts were illuminated for 10 minutes prior to enzyme measurement and then decreased slowly in the dark. measurements of total enzyme activity were unchanged by prior light treatment. initi ...	1989	16666582
activity ratios of ribulose-1,5-bisphosphate carboxylase accurately reflect carbamylation ratios.	activity ratios and carbamylation ratios of ribulose-1,5-bisphosphate carboxylase (rubpcase) were determined for leaves of phaseolus vulgaris and spinacia oleracea exposed to a variety of partial pressures of co(2) and o(2) and photon flux densities (pfd). it was found that activity ratios accurately predicted carbamylation ratios except in extracts from leaves held in low pfd. in particular, it was confirmed that the loss of rubpcase activity in low partial pressure of o(2) and high pfd results ...	1989	16666614
regulation of ribulose-1,5-bisphosphate carboxylase activity in response to diurnal changes in irradiance.	the regulation of ribulose-1,5-bisphosphate (rubp) carboxylase (rubisco) activity and metabolite pool sizes in response to natural diurnal changes in photon flux density (pfd) was examined in three species (phaseolus vulgaris, beta vulgaris, and spinacia oleracea) known to differ in the mechanisms used for this regulation. diurnal regulation of rubisco activity in p. vulgaris was primarily the result of metabolism of the naturally occurring tight-binding inhibitor of rubisco, 2-carboxyarabinitol ...	1989	16666642
inhibition of chloroplastic respiration by osmotic dehydration.	the respiratory capacity of isolated spinach (spinacia oleracea l.) chloroplasts, measured as the rate of (14)co(2) evolved from the oxidative pentose phosphate cycle in darkened chloroplasts exogenously supplied with [(14)c]glucose, was progressively diminished by escalating osmotic dehydration with betaine or sorbitol. comparing the inhibitions of co(2) evolution generated by osmotic dehydration in chloroplasts given c-1 and c-6 labeled glucose, 54% and 84% respectively, indicates that osmotic ...	1989	16666679
effect of light on the chloroplast division cycle and dna synthesis in cultured leaf discs of spinach.	the effects of light on both the division cycle of chloroplasts and the synthesis of chloroplast dna were investigated in cultured discs taken from the distal end of 2-centimeter spinach (spinacia oleracea) leaves. comparisons were made of discs cultured for a maximum of 4 days in a shaking liquid medium under continuous white light, darkness, and of discs cultured for 1 day in light following 3 days in darkness. in continuous white light the shortest generation time of chloroplasts observed in ...	1989	16666681
evidence that ribulose 1,5-bisphosphate (rubp) binds to inactive sites of rubp carboxylase in vivo and an estimate of the rate constant for dissociation.	the binding of ribulose 1,5-bisphosphate (rubp) to inactive (noncarbamylated) sites of the enzyme rubp carboxylase in vivo was investigated in spinacia oleracea and helianthus annuus. the concentrations of rubp and inactive sites were determined in leaf tissue as a function of time after a change to darkness. rubp concentrations fell rapidly after the change to darkness and were approximately equal to the concentration of inactive sites after 60 s. variations in the concentration of inactive sit ...	1989	16666692
evidence for a ferredoxin-dependent choline monooxygenase from spinach chloroplast stroma.	chenopods synthesize betaine in the chloroplast via a two-step oxidation of choline: choline --> betaine aldehyde --> betaine. our previous experiments with intact chloroplasts, and in vivo(18)o(2) labeling studies, led us to propose that the first step is mediated by a monooxygenase which uses photosynthetically generated reducing power (c lerma, ad hanson, d rhodes [1988] plant physiol 88: 695-702). here, we report the detection of such an activity in vitro. in the presence of o(2) and reduced ...	1989	16666757
senescence-induced, thylakoid-bound diisopropylfluorophosphate-binding protein in spinach : induction pattern, localization, and some properties.	changes in diisopropylfluorophosphate (dfp)-binding proteins during development and senescence of spinach (spinacia oleracea) leaves were followed using [(3)h]dfp and sodium dodecylsulfate-polyacrylamide gel electrophoresis-fluorography. experiments using a series of aging stages of leaves attached to plants and ones with detached leaves stored in the dark both showed that a protein of 38 kilodaltons was the only major dfp-binding protein in the membrane fraction and that its dfp-binding increas ...	1989	16666760
a cerulenin insensitive short chain 3-ketoacyl-acyl carrier protein synthase in spinacia oleracea leaves.	a cerulenin insensitive 3-ketoacyl-acyl carrier protein synthase has been assayed in extracts of spinach (spinacia oleracea) leaf. the enzyme was active in the 40 to 80% ammonium sulfate precipitate of whole leaf homogenates and catalyzed the synthesis of acetoacetyl-acyl carrier protein. this condensation reaction was five-fold faster than acetyl-coa:acyl carrier protein transacylase, and the initial rates of acyl-acyl carrier protein synthesis were independent of the presence of cerulenin. in ...	1989	16666765
chloride inhibition of spinach nitrate reductase.	initial rate studies of spinach (spinacia oleracea l.) nitrate reductase showed that nadh:nitrate reductase activity was ionic strength dependent with elevated ionic concentration resulting in inhibition. in contrast, nadh:ferricyanide reductase was markedly less ionic strength dependent. at ph 7.0, nadh:nitrate reductase activity exhibited changes in the v(max) and k(m) for no(3) (-) yielding v(max) values of 6.1 and 4.1 micromoles nadh per minute per nanomoles heme and k(m) values of 13 and 18 ...	1989	16666771
immunodetection of the ferredoxin-nadp oxidoreductase-binding protein complex in thylakoids of different higher plant species.	monospecific polyclonal antibodies against thylakoid ferredoxin-nadp(+) oxidoreductase and its binding protein from spinacia oleracea were used to detect the presence of these proteins in different higher plants, including c(3), c(4), and crassulacean acid metabolism species. a remarkable conservation of antigenic determinants in all the species analyzed was demonstrated for both the reductase and its binding protein. the association of these polypeptides in a complex was detected by immunopreci ...	1989	16666777
an examination of the plastid dna of hypohaploid nicotiana plumbaginifolia plants.	dna was extracted from different morphological types of hypohaploid nicotiana plumbaginifolia plants. the cellular levels of chloroplast dna (expressed as percent of total dna) were found to be approximately two- to threefold higher in two albino hypohaploids than in a green hypohaploid. the level of chloroplast dna in the green hypohaploid was not significantly different from either in vitro or in vivo grown haploid n. plumbaginifolia plants. molecular hybridization with dna probes for the larg ...	1989	16666781
identification and partial characterization of the denaturation transition of the light harvesting complex ii of spinach chloroplast membranes.	differential scanning calorimetry was employed to investigate the structure of spinach (spinacia oleracea) chloroplast membranes. in a low ionic strength hepes-buffered medium, major calorimetric transitions were resolved at 42.5 degrees c. (a), 60.6 degrees c (b), 64.9 degrees c (c(1)), 69.6 degrees c (c(2)), 75.8 degrees c (d), 84.3 degrees c (e), and 88.9 degrees c (f). a lipid melting transition was also commonly seen at 17 degrees c in scans starting at lower temperatures. the d transition ...	1989	16666798
aerobic and anaerobic respiration in the intact spinach chloroplast.	aerobic and anaerobic chloroplastic respiration was monitored by measuring (14)co(2) evolution from [(14)c]glucose in the darkened spinach (spinacia oleracea) chloroplast and by estimating the conversion of fructose 1,6-bisphosphate to glycerate 3-phosphate in the darkened spinach chloroplast in air with o(2) or in n(2) with nitrite or oxaloacetate as electron acceptors. the pathway of (14)co(2) evolution from labeled glucose in the absence and presence of the inhibitors iodoacetamide and glycol ...	1989	16666823
cloning of cdna sequences encoding the calcium-binding protein, calmodulin, from barley (hordeum vulgare l.).	full- and partial-length cdnas encoding calmodulin mrna have been cloned and sequenced from barley (hordeum vulgare l.). barley leaf mrna, size-fractionated in sucrose density gradients, was used to synthesize double-stranded cdna. the cdna was cloned in lambdagt10 and screened with a synthetic, 14-nucleotide oligonucleotide probe, which was designed using the predicted coding sequences of the carboxy termini of spinach and wheat calmodulin proteins. the primary structure of barley calmodulin, p ...	1989	16666833
inactive photosystem ii complexes in leaves : turnover rate and quantitation.	the flash-induced electrochromic shift, measured by the amplitude of the rapid absorbance increase at 518 nanometers (deltaa518), was used to determine the amount of charge separation within photosystems ii and i in spinach (spinacia oleracea l.) leaves. the recovery time of the reaction centers was determined by comparing the amplitudes of deltaa518 induced by two flashes separated by a variable time interval. the recovery of the deltaa518 on the second flash revealed that 20% of the reaction c ...	1989	16666841
sources of carbon for export from spinach leaves throughout the day.	rates of net carbon exchange, export, starch, and sucrose synthesis were measured in leaves of spinach (spinacia oleracea l.) throughout a 14-hour period of sinusoidal light to determine the sources of carbon contributing to export. net carbon exchange rate closely followed light level, but export remained relatively constant throughout the day. in the morning when photosynthesis was low, starch degradation provided most of the carbon for export, while accumulated sucrose was exported during the ...	1989	16666868
fructose 2,6-bisphosphate hydrolyzing enzymes in higher plants.	the phosphatases that hydrolyze fructose 2,6-bisphosphate in a crude spinach (spinacia oleracea l.) leaf extract were separated by chromatography on blue sepharose, into three fractions, referred to as phosphatases i, ii, and iii, which were further purified by various means. phosphatase i hydrolyzed fructose 2,6-bisphosphate, with a k(m) value of 30 micromolar, to a mixture of fructose 2-phosphate (90%) and fructose 6-phosphate (10%). it acted on a wide range of substrates and had a maximal act ...	1989	16666884
cytosolic phosphofructokinase from spinach leaves : i. purification, characteristics, and regulation.	cytosolic atp-dependent phosphofructokinase (pfk) from spinach leaves (spinacia oleracea l.) was enriched 2600-fold by (nh(4))(2)so(4) fractionation, deae anion exchange chromatography, blue sepharose cl-6b, and atp agarose type 3-affinity chromatography. the final preparation had a specific activity of 417 nkat per milligram protein and exhibited four bands between 50 and 70 kilodaltons following denaturing electrophoresis. only one band of atp- and fructose 6-phosphate (f-6-p)-dependent, pisti ...	1989	16666957
cytosolic phosphofructokinase from spinach leaves : ii. affinity for mg and nucleoside phosphates.	cytosolic atp-phosphofructokinase (pfk) from spinach leaves (spinacia oleracea l.) was inhibited by submillimolar concentrations of free mg(2+). the free mg(2+) concentration required for 50% inhibition of pfk activity was 0.22 millimolar. inhibition by free mg(2+) was independent of the mgatp(2-) concentration. inorganic phosphate (pi) reduces the inhibition of pfk activity by mg(2+). free atp (atp(4-)) also inhibits pfk activity. for free atp the inhibition of pfk activity was dependent on the ...	1989	16666958
protoplast volume:water potential relationship and bound water fraction in spinach leaves.	methods used to estimate the (nonosmotic) bound water fraction (bwf) (i.e. apoplast water) of spinach (spinacia oleracea l.) leaves were evaluated. studies using three different methods of pressure/volume (p/v) curve construction all resulted in a similar calculation of bwf; approximately 40%. the theoretically derived bwf, and the water potential (psi(w))/relative water content relationship established from p/v curves were used to establish the relationship between protoplast (i.e. symplast) vo ...	1989	16666983
effects of inorganic phosphate on the light dependent thylakoid energization of intact spinach chloroplasts.	the light dependent energization of the thylakoid membrane was analyzed in isolated intact spinach (spinacia oleracea l.) chloroplasts incubated with different concentrations of inorganic phosphate (pi). two independent methods were used: (a) the accumulation of [(14)c]5,5-dimethyl-2,4-oxazolidinedione and [(14)c] methylamine; (b) the energy dependent chlorophyll fluorescence quenching. the inhibition of co(2) fixation by superoptimal medium pi or by adding glyceraldehyde-an inhibitor of the cal ...	1989	16667000
direct measurement of k channels in thylakoid membranes by incorporation of vesicles into planar lipid bilayers.	light-driven electron transfer reactions cause the active accumulation of protons inside thylakoids, yet at steady state the electrical potential difference across the thylakoid membrane is very small; therefore, there must be a flux of other ions to balance the charge that would otherwise be built up by the net movement of h(+). this paper presents direct measurements of ion movements through channels in the thylakoid membrane. these were made possible by fusing thylakoid vesicles from spinach ...	1989	16667005
species and environmental variations in the effect of inorganic phosphate on sucrose-phosphate synthase activity : reliability of assays based upon udp formation.	the effect of inorganic phosphate (pi) on sucrose-phosphate synthase (sps) activity was determined for the enzyme from five plant species (nicotiana tabacum l., spinacia oleracea l., triticum aestivum l., zea mays l., glycine max l.) using two assay methods. the assay method based on determination of uridine diphosphate glucose- (udpg) and fructose-6-phosphate-dependent sucrose formation was linear up to 15 minutes for all species tested. when assayed in this way, the effect of pi at levels of 5 ...	1989	16667054
analysis of chromophytic and rhodophytic ribulose-1,5-bisphosphate carboxylase indicates extensive structural and functional similarities among evolutionarily diverse algae.	ribulose-1,5-bisphosphate carboxylase (rubisco) from the algae olisthodiscus luteus (chromophyte) and griffithsia pacifica (rhodophyte) are remarkably similar to each other. however, both enzymes differ significantly in the structure and function when compared to rubisco from green algae and land plants. analysis of purified rubisco from o. luteus and g. pacifica indicates that the size of the holoenzyme and stoichiometry of the 55 and 15 kilodalton subunit polypeptides are approximately 550 kil ...	1989	16667160
low co(2) prevents nitrate reduction in leaves.	the correlation between co(2) assimilation and nitrate reduction in detached spinach (spinacia oleracea l.) leaves was examined by measuring light-dependent changes in leaf nitrate levels in response to mild water stress and to artificially imposed co(2) deficiency. the level of extractable nitrate reductase (nr) activity was also measured. the results are: (a) in the light, detached turgid spinach leaves reduced nitrate stored in the vacuoles of mesophyll cells at rates between 3 and 10 micromo ...	1989	16667163
structural similarities between spinach chloroplast and cytosolic class i fructose 1,6-bisphosphate aldolases : immunochemical and amino-terminal amino acid sequence analysis.	immunochemical studies using polyclonal antisera prepared individually against highly purified cytosolic and chloroplast spinach leaf (spinacia oleracea) fructose bisphosphate aldolases showed significant cross reaction between both forms of spinach aldolase and their heterologous antisera. the individual cross reactions were estimated to be approximately 50% in both cases under conditions of antibody saturation using a highly sensitive enzyme-linked immunosorbent assay. in contrast, the class i ...	1989	16667191
evidence for a universal pathway of abscisic acid biosynthesis in higher plants from o incorporation patterns.	previous labeling studies of abscisic acid (aba) with (18)o(2) have been mainly conducted with water-stressed leaves. in this study, (18)o incorporation into aba of stressed leaves of various species was compared with (18)o labeling of aba of turgid leaves and of fruit tissue in different stages of ripening. in stressed leaves of all six species investigated, avocado (persea americana), barley (hordeum vulgare), bean (phaseolus vulgaris), cocklebur (xanthium strumarium), spinach (spinacia olerac ...	1989	16667222
a novel role for light in the activation of ribulosebisphosphate carboxylase/oxygenase.	light stimulated the activation of ribulosebisphosphate carboxylase/oxygenase (rubisco) in a buffered lysed chloroplast system in the presence of saturating concentrations of atp. this indicates a role for light in the rubisco activase activation system in addition to the previously identified requirement for the synthesis of atp. rubisco activation was nearly as great at low irradiance (10 micromoles of photons per square meter per second) as at high irradiance (1000 micromoles of photons per s ...	1990	16667230
spinach chloroplastic carbonic anhydrase: nucleotide sequence analysis of cdna.	we have determined the nucleotide sequence of a cdna encoding spinach (spinacia oleracea) chloroplastic carbonic anhydrase (ca). the open reading frame encodes a protein consisting of a transit peptide and a mature ca protein with a predicted mass of 24, 116 daltons. this represents the first report of a nucleotide sequence of a plant ca.	1990	16667262
identification of the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase as a substrate for transglutaminase in medicago sativa l. (alfalfa).	extracts prepared from floral meristematic tissue of alfalfa (medicago sativa l.) were investigated for expression of the enzyme transglutaminase in order to identify the major protein substrate for transglutaminase-directed modifications among plant proteins. the large polymorphic subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase in alfalfa, with molecular weights of 52,700 and 57,600, are major substrates for transglutaminase in these extracts. this was established by: (a) covalent c ...	1990	16667270
subcellular compartmentation of uridine nucleotides and nucleoside-5' -diphosphate kinase in leaves.	the subcellular compartmentation of nucleoside diphosphate kinase (ec 2.7.4.6) and the uridine nucleotides has been studied in leaves. membrane filtration of barley (hordeum vulgare l.) leaf mesophyll protoplasts and differential centrifugation of spinach (spinacia oleracea l.) leaf extracts showed that about half the nucleoside diphosphate kinase is present in the cytosol. the activity is adequate to account for the turnover of utp and udp during photosynthetic sucrose synthesis. nonaqueous den ...	1990	16667327
on the regulation of spinach nitrate reductase.	a coupled assay has been worked out to study spinach (spinacea oleracea l.) nitrate reductase under low, more physiological concentrations of nadh. in this assay the reduction of nitrate is coupled to the oxidation of malate catalyzed by spinach nad-malate dehydrogenase. the use of this coupled system allows the assay of nitrate reductase activity at steady-state concentrations of nadh below micromolar. we have used this coupled assay to study the kinetic parameters of spinach nitrate reductase ...	1990	16667335
purification by immunoadsorption and immunochemical properties of nadp-dependent malic enzymes from leaves of c(3), c(4), and crassulacean acid metabolism plants.	nadp:malic enzyme from corn (zea mays l.) leaves was purified by conventional techniques to apparent homogeneity as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. antibodies raised against this protein in rabbits were purified, coupled covalently to protein a-sepharose cl-4b, and used as an immunoaffinity resin to purify the nadp:malic enzymes of the c(3) plants spinach (spinacia oleracea l.) and wheat (triticum aestivum l.), of the crassulacean acid metabolism (cam) plant ...	1990	16667339
oxidation versus reductive detoxification of so(2) by chloroplasts.	intact chloroplasts isolated from spinach (spinacia oleracea l. cv yates) both oxidized and reduced added sulfite in the light. oxidation was fast only when endogenous superoxide dismutase was inhibited by cyanide. it was largely suppressed by scavengers of oxygen radicals. after addition of o-acetylserine, chloroplasts reduced sulfite to cysteine and exhibited sulfite-dependent oxygen evolution. cysteine synthesis from sulfite was faster than from sulfate. the results are discussed in relation ...	1990	16667358
nitrite photoreduction in vivo is inhibited by oxygen.	it was hypothesized previously that an o(2) inhibition of no(2) (-) photoreduction would reflect a competition between o(2) and no(2) (-) for electrons from ferredoxin at the site of plastid nitrite reductase. in order to test this in vivo, intact spinach (spinacia oleracea l.) leaf chloroplast and mesophyll cell isolates held in high light were aerated with streams of 20% o(2)/80% n(2) (250 micromolar o(2) in aqueous solution) or, alternatively, streams of 100% n(2). bicarbonate plus co(2) and ...	1990	16667362
chlamydomonas reinhardtii phosphoribulokinase : sequence, purification, and kinetics.	the sequence and kinetic properties of phosphoribulokinase purified from chlamydomonas reinhardtii were determined and compared with the spinach (spinacea oleracea) enzyme. chlamydomonas phosphoribulokinase was purified to apparent homogeneity, with a specific activity of 410 micromoles per minute per milligram. polyclonal antibodies to the purified protein were used to isolate a chlamydomonas cdna clone, which, upon sequencing, was found to contain the entire coding region. the transit peptide ...	1990	16667433
status of the substrate binding sites of ribulose bisphosphate carboxylase as determined with 2-c-carboxyarabinitol 1,5-bisphosphate.	the properties of the tight and specific binding of 2-c-carboxy-d-arabinitol 1,5-bisphosphate (cabp), which occurs only to reaction sites of ribulose 1,5-bisphosphate carboxylase (rubisco) that are activated by co(2) and mg(2+), were studied. with fully active purified spinach (spinacia oleracea) rubisco the rate of tight binding of [(14)c]cabp fit a multiple exponential rate equation with half of the sites binding with a rate constant of 40 per minute and the second half of the sites binding at ...	1990	16667442
isolation and characterization of the cytosolic and chloroplastic 3-phosphoglycerate kinase from spinach leaves.	the cytosol and chloroplast 3-phosphoglycerate kinases (3-pgk) from spinach (spinacia oleracea l.) were purifled to apparent homogeneity. the procedure included a conventional anion-exchange chromatography on deae-cellulose and mainly a series of hplc columns. the charge differences of the two isoenzymes were so small that separation was only successful by anion-exchange chromatography on a hplc synchropak ax 300 column. the portion of the two isoenzmyes in leaf tissue was estimated as 5% and 95 ...	1990	16667463
shikimate kinase from spinach chloroplasts : purification, characterization, and regulatory function in aromatic amino acid biosynthesis.	shikimate kinase was purified to near homogenity from spinach spinacia oleracea l. chloroplasts and found to consist of a single 31 kilodalton polypeptide. the purified enzyme was unstable, but could be stabilized by a variety of added proteins, including oxidized and reduced thioredoxins. whereas the isolated enzyme was stimulated by mono- and dithiol reagents, the enzyme in intact chloroplasts was unaffected by added thiols and showed only minor response to dark/light transitions. these result ...	1990	16667533
thermal dependence of the apparent k(m) of glutathione reductases from three plant species.	the thermal dependencies of the apparent k(m) of the glutathione reductases from spinach (spinacia oleracea l.) corn (zea mays l.), and cucumber (cucumis sativus l.) were determined. the apparent k(m) of the enzymes were found to vary up to 9-fold between 12.5 and 45 degrees c. values of the apparent k(m) in excess of 200% of the observed minimum are suggested to be detrimental to the normal function of the enzyme. we propose the term "thermal kinetic window" to describe to the range of temperat ...	1990	16667543
sulfhydryl reagents and energy-linked reactions in monocot thylakoids.	monofunctional maleimides have been used to covalently modify the coupling factor protein of monocot thylakoid membranes. as with dicot thylakoids, incubation of the monocot thylakoids with maleimides in the light but not in the dark results in inhibition of both atp synthesis and hydrolysis. in the dark, sites on the gamma and epsilon subunits of maize zea mays coupling factor 1 are modified after incubation of maize mesophyll thylakoids with the fluorescent maleimide n-(anilinonaphthyl-4) male ...	1990	16667548
carbon metabolism in spinach leaves as affected by leaf age and phosphorus and sulfur nutrition.	spinach (spinacea oleracea) plants were grown either continuously on complete nutrient solutions or for 2 weeks on media deficient in phosphate or sulfate. to characterize leaf carbohydrate metabolism, levels of phosphorylated intermediates, activities of enzymes involved in photosynthetic carbon metabolism, contents of soluble and acid hydrolyzable sugars were measured in leaves differing in age and mineral status and related to leaf rates of photosynthesis and assimilate partitioning. concentr ...	1990	16667581
purification and characterization of a ferredoxin-nadp oxidoreductase-like enzyme from radish root tissues.	an enzyme able to reduce cytochrome c via ferredoxin in the presence of nadph, was isolated, purified from radish (raphanus sativus var acanthiformis cultivar miyashige) roots and characterized. the enzyme was purified by deae-cellulose, blue-cellulofine, ferredoxin-sepharose 4b, and sephadex g-100 column chromatography. molecular mass of the enzyme was estimated to be 33,000 and 35,000 daltons by sephadex g-100 gel filtration and sds-page, respectively. its absorption spectrum suggested that th ...	1990	16667598
biosynthesis of digalactosyldiacylglycerol in plastids from 16:3 and 18:3 plants.	intact chloroplasts isolated from leaves of eight species of 16:3 and 18:3 plants and chromoplasts isolated from narcissus pseudonarcissus l. flowers synthesize galactose-labeled mono-, di-, and trigalactosyldiacylglycerol (mgdg, dgdg, and tgdg) when incubated with udp-[6-(3)h]galactose. in all plastids, galactolipid synthesis, and especially synthesis of dgdg and tgdg, is reduced by treatment of the organelles with the nonpenetrating protease thermolysin. envelope membranes isolated from thermo ...	1990	16667615
cause for dark, chilling-induced inactivation of photosynthetic oxygen-evolving system in cucumber leaves.	effects on oxygen evolution of the storage of detached cucumber (cucumis sativus) leaves at 0 degrees c in the dark were investigated with thylakoids and oxygen-evolving photosystem ii membranes isolated from stored leaves. the cold and dark treatment of leaves selectively inactivated electron transport on the oxidizing side of photosystem ii. photosystem ii membranes isolated from treated leaves were largely depleted of two proteins of 20 and 14 kilodaltons, which correspond to the extrinsic 23 ...	1990	16667624
activity of ribulose 1,5-bisphosphate carboxylase oxygenase as a function of storage conditions.	optimal storage conditions to retain ribulose 1, 5-bisphosphate carboxylase/oxygenase (rubisco) activity were investigated. the soluble spinach (spinacia oleracea) enzyme was pretreated with its activators, mg(2+) and hco(3) (-), and then stored for up to 30 days at 4 or -18 degrees c or in liquid n(2). cold inactivation and conformational changes were suggested to be involved during rubisco storage in the cold, leading to its inactivation. pretreatment of the enzyme with mg(2+) and co(2) and su ...	1990	16667648
involvement of ferredoxin in desaturation of lipid-bound oleate in chloroplasts.	intact spinach (spinacia oleracea) chloroplasts, pulse-labeled with [(14)c]acetate, desaturate newly formed fatty acids as ester groups of monogalactosyl diacylglycerol in a subsequent chase in the dark. rupture of pulse-labeled chloroplasts by addition of a detergent solution 3-([3-cholamidopropyl]dimethylammonio)-1-propane sulfonate preserves part of this desaturation activity. direct addition of different free fatty acids together with appropriate cofactors to detergent-ruptured chloroplasts ...	1990	16667689
determination of oxygen emission and uptake in leaves by pulsed, time resolved photoacoustics.	pulsed, time resolved photoacoustics has sufficient sensitivity to determine oxygen emission and uptake by single turnover flashes to leaves. the advantage over previous methodologies is that when combined with single turnover flashes the kinetics of the thermal and the gas signals can be resolved to 0.1 millisecond and separated. the s-state oscillations of oxygen formation are readily observed. the gas signal from common spongy leaves such as spinach (spinacia sp.), japanese andromeda (pieris ...	1990	16667697
conversion of monogalactosyldiacylglycerols to triacylglycerols in ozone-fumigated spinach leaves.	molecular species and fatty acid distribution of triacylglycerol (tg) accumulated in spinach (spinacia oleracea l.) leaves fumigated with ozone (0.5 microliter per liter) were compared with those of monogalactosyldiacylglycerol (mgdg). analysis of positional distribution of the fatty acids in mgdg and the accumulated tg by the enzymatic digestion method showed that hexadecatrienoate (16:3) was restricted to sn-2 position of the glycerol backbone in both mgdg and tg, whereas alpha-linolenate (18: ...	1990	16667777
pathway for the synthesis of triacylglycerols from monogalactosyldiacylglycerols in ozone-fumigated spinach leaves.	when the upper leaf surface of spinach (spinacia oleracea l.) plants was treated with [1-(14)c]acetate and grown for 2 days, (14)c was effectively incorporated into acyl moieties of leaf lipids in ratios approximately their composition by mass. fumigation of the plants with ozone (0.5 microliter per liter) caused a redistribution of (14)c among lipid classes, i.e. a marked increase of (14)c content in triacylglycerol (tg) and 1,2-diacylglycerol (1,2-dg) and a decrease of label in monogalactosyld ...	1990	16667778
free fatty acids regulate two galactosyltransferases in chloroplast envelope membranes isolated from spinach leaves.	effects of mgcl(2) and free fatty acids (ffa) on galactolipid:galactolipid galactosyltransferase (gggt) and udp-galactose: 1,2-diacylglycerol galactosyltransferase (udgt) in chloroplast envelope membranes isolated from spinach (spinacia oleracea l.) leaves were examined. gggt activity was sigmoidally stimulated by mgcl(2) with a saturated concentration of more than 5 millimolar. free alpha-linolenic acid (18:3) caused a drastic increase in gggt activity under limiting concentrations of mgcl(2), ...	1990	16667779
localization of atp sulfurylase and o-acetylserine(thiol)lyase in spinach leaves.	the intracellular compartmentation of atp sulfurylase and o-acetylserine(thiol)lyase in spinach (spinacia oleracea l.) leaves has been investigated by isolation of organelles and fractionation of protoplasts. atp sulfurylase is located predominantly in the chloroplasts, but is also present in the cytosol. no evidence was found for atp sulfurylase activity in the mitochondria. two forms of atp sulfurylase were separated by anion-exchange chromatography. the more abundant form is present in the ch ...	1990	16667839
conversion of l-sorbosone to l-ascorbic acid by a nadp-dependent dehydrogenase in bean and spinach leaf.	an nadp-dependent dehydrogenase catalyzing the conversion of l-sorbosone to l-ascorbic acid has been isolated from phaseolus vulgaris l. and spinacia oleracea l. and partially purified. it is stable at -20 degrees c for up to 8 months. molecular masses, as determined by gel filtration, were 21 and 29 kilodaltons for bean and spinach enzymes, respectively. k(m) for sorbosone were 12 +/- 2 and 18 +/- 2 millimolar and for nadp(+), 0.14 +/- 0.05 and 1.2 +/- 0.5 millimolar, for bean and spinach, resp ...	1990	16667860
d-glucosone and l-sorbosone, putative intermediates of l-ascorbic acid biosynthesis in detached bean and spinach leaves.	d-[6-(14)c]glucosone that had been prepared enzymically from d-[6-(14)c]glucose was used to compare relative efficiencies of these two sugars for l-ascorbic acid (aa) biosynthesis in detached bean (phaseolus vulgaris l., cv california small white) apices and 4-week-old spinach (spinacia oleracea l., cv giant noble) leaves. at tracer concentration, (14)c from glucosone was utilized by spinach leaves for aa biosynthesis much more effectively than glucose. carbon-14 from [6-(14)c]glucose underwent ...	1990	16667861
polysaccharide fraction from higher plants which strongly interacts with the cytosolic phosphorylase isozyme : i. isolation and characterization.	from leaves of spinacia oleracea l. or from pisum sativum l. and from cotyledons of germinating pea seeds a high molecular weight polysaccharide fraction was isolated. the apparent size of the fraction, as determined by gel filtration, was similar to that of dextran blue. following acid hydrolysis the monomer content of the polysaccharide preparation was studied using high pressure liquid and thin layer chromatography. glucose, galactose, arabinose, and ribose were the main monosaccharide compou ...	1990	16667877
effect of growth temperature and temperature shifts on spinach leaf morphology and photosynthesis.	the growth kinetics of spinach plants (spinacia oleracea l. cv savoy) grown at 5 degrees c or 16 degrees c were determined to allow us to compare leaf tissues of the same developmental stage rather than chronological age. the second leaf pairs reached full expansion at a plant age of 32 and 92 days for the 16 degrees c and 5 degrees c plants, respectively. growth at 5 degrees c resulted in an increased leaf area, dry weight, dry weight per area, and leaf thickness. despite these changes, pigment ...	1990	16667923
primary structure of chlamydomonas reinhardtii ribulose 1,5-bisphosphate carboxylase/oxygenase activase and evidence for a single polypeptide.	immunoblot analysis of ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) activase from the green alga chlamydomonas reinhardtii indicated the presence of a single polypeptide. this observation contrasts with the spinacea oleracea (spinach) and arabidopsis thaliana proteins, in which two polypeptide species are generated by alternative pre-mrna splicing. a chlamydomonas rubisco activase cdna clone containing the entire coding region was isolated and sequenced. the open reading frame encod ...	1990	16667924
roles of atp and nadph in formation of the fe-s cluster of spinach ferredoxin.	ferredoxin (fd) in higher plants is encoded by a nuclear gene, synthesized in the cytoplasm as a larger precursor, and imported into the chloroplast, where it is proteolytically processed, and assembled with the [2fe-2s] cluster. the final step in the biosynthetic pathway of fd can be analyzed by a reconstitution system composed of isolated chloroplasts and [(35)s]cysteine, in which [(35)s]sulfide and iron are incorporated into fd to build up the (35)s-labeled fe-s cluster. although a lysed chlo ...	1991	16667935
isolation of a cdna clone for spinach lipid transfer protein and evidence that the protein is synthesized by the secretory pathway.	a cdna clone encoding a nonspecific lipid transfer protein from spinach (spinacia oleracea) was isolated by probing a library with synthetic oligonucleotides based on the amino acid sequence of the protein. determination of the dna sequence indicated a 354-nucleotide open reading frame which encodes a 118-amino acid residue polypeptide. the first 26 amino acids of the open reading frame, which are not present in the mature protein, have all the characteristics of a signal sequence which is norma ...	1991	16667945
isolation and characterization of a cdna coding for pea chloroplastic carbonic anhydrase.	using a polyclonal antibody generated against the purified pea (pisum sativum) carbonic anhydrase (ca) monomeric species, we have isolated and characterized a cdna coding for this enzyme. protein sequence analysis was used to confirm the identity of the clone. the presence of a large transit peptide suggests that ca is transported into the chloroplast and then processed to the mature size of approximately 26 kilodaltons. northern hybridization, using the ca cdna as a probe of total leaf rna, rev ...	1991	16667962
inactivation of highly activated spinach leaf sucrose-phosphate synthase by dephosphorylation.	spinach (spinacia oleracea l.) leaf sucrose-phosphate synthase (sps) can be phosphorylated and inactivated in vitro with [gamma-(32)p]atp (jla huber, sc huber, th nielsen [1989] arch biochem biophys 270: 681-690). thus, it was surprising to find that sps, extracted from leaves fed mannose in the light to highly activate the enzyme, could be inactivated in an atp-independent manner when desalted crude extracts were preincubated at 25 degrees c before assay. the "spontaneous" inactivation involved ...	1991	16667968
nadh-ferricyanide reductase of leaf plasma membranes : partial purification and immunological relation to potato tuber microsomal nadh-ferricyanide reductase and spinach leaf nadh-nitrate reductase.	plasma membranes obtained by two-phase partitioning of microsomal fractions from spinach (spinacea oleracea l. cv medania) and sugar beet leaves (beta vulgaris l.) contained relatively high nadh-ferricyanide reductase and nadh-nitrate reductase (nr; ec 1.6.6.1) activities. both of these activities were latent. to investigate whether these activities were due to the same enzyme, plasma membrane polypeptides were separated with sds-page and analyzed with immunoblotting methods. antibodies raised a ...	1991	16667982
formation of the fe-s cluster of ferredoxin in lysed spinach chloroplasts.	in vitro formation of the (35)s-labeled fe-s cluster of ferredoxin (fd) has been achieved by incubating apo-fd and [(35)s]cysteine with osmotically lysed chloroplasts of spinach (spinacia oleracea). correct integration of the (35)s-labeled fe-s cluster into fd was verified on the basis of the following: (a) under nondenaturing conditions, (35)s-labeled holo-fd showed the same electrophoretic mobility as authentic holo-fd; (b) (35)s-labeled holo-fd showed an ability to bind fd-nadp(+) reductase; ...	1991	16667987
nonsteady-state photosynthesis following an increase in photon flux density (pfd) : effects of magnitude and duration of initial pfd.	the response of photosynthesis to an increase in photon flux density (pfd) from low to higher pfd was investigated using spinach (spinacia oleracea l.). the time-course for this response was qualitatively similar to that observed for a dark-to-high-pfd transition, showing an initial, rapid increase in photosynthesis over the first minute or so, followed by a slower increase lasting 5 to 10 minutes. this slow increase was approximately exponential and could be linearized using a semilogarithmic p ...	1991	16668012