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1.
Summary A highly calcareous clay soil was treated with six iron chelates, those formed by RA 155, RA 156, RA 157, RA 159, ATA or HEG, and then extracted with an aqueous solution after intervals of up to 30 days.About 80% of total RA 155 was recovered at each sampling time, but after 15 days approximately one-third of the iron in it had been replaced by calcium. Some of the Fe-RA 156 and Fe-RA 159 was sorbed by the clay, but no calcium was found to have replaced iron chelated with RA 156, RA 157 or RA 159.The four chelates of the RA series were labelled with Fe59. The amount of isotopic exchange taking place between the Fe59 and soil iron was found to be negligible.A very low percentage of Fe-ATA and Fe-HEG was recovered from the soil. Approximately 50% of the Fe-ATA was sorbed by the clay, and in the remainder the chelated iron was replaced by calcium. The cause of the loss of Fe-HEG could not be determined. 相似文献
2.
Summary Fe-EDTA and Fe-HEEDTA, labelled with Fe59, were applied at rates of 10 and 100 ppm iron to 50-g samples of dry soil, which were then stored for periods ranging from one to fifteen days before extracting with water.The analyses of the extracts lead to the following general conclusions.1. The decrease in soluble iron could be attributed to both sorption of chelate anions by the clay and to replacement of iron by calcium in the chelate molecule.2. The amount of each chelate sorbed changed little with time and was proportional to the quantity applied. More HEEDTA was sorbed than EDTA.3. The initial decrease in the concentration of soluble iron was rapid for both chelates, but was the greater for Fe-HEEDTA.4. The precipitation of iron from the soluble Fe-HEEDTA was slower than from Fe-EDTA, so that fifteen days after treatment more soluble iron was obtained from the Fe-HEEDTA treatments.5. Marked increases in the recoveries of Fe-EDTA were made when the treated soils were sealed within small containers, compared with those allowed free access to the air. Comparable treatments using Fe-HEEDTA had a much smaller effect.6. Isotopic exchange of Fe59 with natural soil iron was greater in the treatments with 10 ppm chelated iron than the 100 ppm level. Fe-HEEDTA was subject to more exchange than Fe-EDTA at both levels.These results are discussed in relation to the treatment of soils with iron chelates for the control of lime-induced chlorosis, and to the importance of isotopic exchange when using chelates labelled with radioactive iron in soil. 相似文献
3.
Summary Laboratory incubation studies on the reactions of Fe-DTPA, Fe-EDTA, Fe-citrate and Fe-fulvate with a calcareous soil indicated that Fe3+ was very rapidly displaced by Ca2+, Mg2+, Zn2+ and Cu2+ ions. The displacement of iron was in the reverse order of the stability of the Fe-chelates. The activity of Fe3+, Ca2+, Mg2+, Zn2+ and Cu2+ tended to attain a constant value with time. Application of chelating agents to a calcareous soil mobilized different amounts of iron as defined by their relative stability and cation competition. The degree of mobilization increased with increasing levels of applied chelating agents. A significant negative correlation (r = –0.77)* was observed between pH and DTPA-extractable iron. Results of greenhouse experiment showed significant increase in the dry matter yield and iron uptake by corn plants upon application of iron-chelates. The chelates enhance the uptake of both native and applied sources. The effectiveness of the chelates used was in the order of their capacity to maintain iron in soluble form in the soil solution. These results suggest that iron nutrition of plants in calcareous soils can be effectively regulated by the application of iron chelated by natural or synthetic water-soluble chelating agents. 相似文献
4.
Summary The behaviour of the metal chelates Mn-EDTA, Mn-DTPA, Mn-EDDHA, Fe-EDTA, Fe-DTPA and Fe-EDDHA in calcareous soils and their
availability to plants were studied.
The effectiveness of a metal chelate was shown to depend on its stability, the fixation capacity in the soil and its toxicity
to the plant. Incorporation of Fe-DTPA into a framework of silica molecules prevents the fixation of Fe-DTPA in the soil.
Fe-DTPA and Fe-EDDHA cause a reduction in the manganese uptake of the plant.
The most striking result was the behaviour of Mn-DTPA in calcareous soils. Partial replacement of manganese in the chelate
by iron from the soil makes this chelate useful for supplying the plant with both iron and manganese. Mn-DTPA appears to be
the ideal type of chelate for the correction of chlorosis in the Netherlands, but unfortunately is not yet commercially available. 相似文献
5.
The most effective and common Fe fertilisers in general are EDDHA and EDDHMA Fe chelates because they are highly stable ferric complexes in neutral and alkaline solutions. EDDHSA and EDDCHA iron chelates were introduced in the market recently. Commercial Fe chelates have two Fe fractions, chelated Fe and non-chelated Fe. The latter is bonded to by-products produced during the synthesis of the chelating agent. The effectiveness of Fe chelates depends on their ability to maintain Fe in the soil solution despite simultaneous equilibrium of Fe chelate with many cations, such as Ca2+. The main aim of this work was to test the possible agricultural use of EDDHSA and EDDCHA Fe chelates. The pH-Ca2+ effect on soluble and chelated Fe (pH ranging from 2 to 12) and the interaction of Fe chelates with soils and soil phases (ferrihydrite, acid peat, calcium carbonate and Ca montmorillonite) are presented. The results demonstrated that EDDHA, EDDHMA, EDDHSA and EDDCHA in solution remain fully associated with Fe from pH 4 to 9 despite competition with Ca. Among soil materials, ferrihydrite and acid peat retain both chelated and non-chelated Fe to the greatest extent. The type of chelating agent is a factor that affects chelated Fe availability in soil. FeEDDHA and FeEDDHMA were retained more by soil surfaces than FeEDDHSA and FeEDDCHA. Commercial Fe chelates present a large amount of soluble, non-chelated Fe and make Cu soluble in soils, which may be due to non-chelated Fe being displaced by Cu. 相似文献
6.
Courtney D. Gress Ron G. Treble Carlyn J. Matz Harold G. Weger 《Journal of phycology》2004,40(5):879-886
Iron acquisition from various ferric chelates and colloids was studied using iron‐limited cells of Anabaena flos‐aquae (Lyng.) Brèb UTEX 1444, a cyanobacterial strain that produces high levels of siderophores under iron limitation. Various chelators of greatly varying affinity for Fe3+ (HEDTA, EDDHA, desferrioxamine mesylate, HBED, 8‐hydroxyquinoline) were assayed for the degree of iron acquisition by iron‐limited cyanobacterial cells. Iron uptake rates (measured by graphite furnace atomic absorption spectrometry) varied approximately inversely with calculated [Fe3+] (calculated as pFe) and decreased with increasing chelator‐to‐iron ratio. No iron uptake was observed when Fe3+ was chelated with HBED, the strongest of the tested chelators. Iron‐limited Anabaena cells were able to take up iron from 8‐hydroxyquinoline (oxine or 8HQ), a compound sometimes used to quantify aquatic iron bioavailability. Iron bound to purified humic acid was poorly available but did support some growth at high humic acid concentrations. These results suggest that for cyanobacteria, even tightly bound iron is biologically available, including to a limited extent iron bound to humic acids. However, iron bound to some extremely strong chelators (e.g. HBED) is likely to be biologically unavailable. 相似文献
7.
Kenji Fukuzawa Yasuaki Saitoh Kentaro Kogure Akira Tokumura Akira Shibata 《生物化学与生物物理学报:生物膜》2005,1668(1):145-155
Albumin is supposed to be the major antioxidant circulating in blood. This study examined the prevention of membrane lipid peroxidation by bovine serum albumin (BSA). Lipid peroxidation was induced by the exposing of enzymatically generated superoxide radicals to egg yolk phosphatidylcholine liposomes incorporating lipids with different charges in the presence of chelated iron catalysts. We used three kinds of Fe3+-chelates, which initiated reactions that were dependent on membrane charge: Fe3+-EDTA and Fe3+-EGTA catalyzed peroxidation in positively and negatively charged liposomes, respectively, and Fe3+-NTA, a renal carcinogen, catalyzed the reaction in liposomes of either charge. Fe3+-chelates initiated more lipid peroxidation in liposomes with increased zeta potentials, followed by an increase of their availability for the initiation of the reaction at the membrane surface. BSA inhibits lipid peroxidation by preventing the interaction of iron chelate with membranes, followed by a decrease of its availability in a charge-dependent manner depending on the iron-chelate concentration: one is accompanied and the other is unaccompanied by a change in the membrane charge. The inhibitory effect of BSA in the former at high concentrations of iron chelate would be attributed to its electrostatic binding with oppositely charged membranes. The inhibitory effect in the latter at low concentrations of iron chelate would be caused by BSA binding with iron chelates and keeping them away from membrane surface where lipid peroxidation is initiated. Although these results warrant further in vivo investigation, it was concluded that BSA inhibits membrane lipid peroxidation by decreasing the availability of iron for the initiation of membrane lipid peroxidation, in addition to trapping active oxygens and free radicals. 相似文献
8.
Iron requirement and iron uptake from various iron compounds by different plant species 总被引:2,自引:1,他引:1
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Christ RA 《Plant physiology》1974,54(4):582-585
The Fe requirements of four monocotyledonous plant species (Avena sativa L., Triticum aestivum L., Oryza sativa L., Zea mays L.) and of three dicotyledonous species (Lycopersicum esculentum Mill., Cucumis sativus L., Glycine maxima (L.) Merr.) in hydroponic cultures were ascertained. Fe was given as NaFe-EDDHA chelate (Fe ethylenediamine di (O-hydroxyphenylacetate). I found that the monocotyledonous species required a substantially higher Fe concentration in the nutrient solution in order to attain optimum growth than did the dicotyledonous species. Analyses showed that the process of iron uptake was less efficient with the monocotyledonous species. When the results obtained by using chelated Fe were compared with those using ionic Fe, it was shown that the inefficient species were equally inefficient in utilizing Fe3+ ions. However, the differences between the efficient and the inefficient species disappeared when Fe2+ was used. This confirms the work of others who postulated that Fe3+ is reduced before uptake of chelated iron by the root. In addition, it was shown that reduction also takes place when Fe is used in ionic form. The efficiency of Fe uptake seems to depend on the efficiency of the root system of the particular plant species in reducing Fe3+. The removal of Fe from the chelate complex after reduction to Fe2+ seems to present no difficulties to the various plant species. 相似文献
9.
Ignatova Milena Manolova Nevena Rashkov Ilia Vassileva Valya Ignatov George 《Plant and Soil》2000,227(1-2):27-34
The efficacy of Fe3+ complexes of polyethers with 8-quinolinol (8QOH) chelating groups attached to the polymer chain at different positions of
the aromatic ring or having different chain length for remedying the iron-deficient maize plants was evaluated. The efficacy
of chelates of polymers having terminal 8QOH residues was compared with that of complexes of ethylenediaminetetraacetic acid,
8QOH, mixtures of commercial polyethers with isopropylamino end-groups and 8QOH or FeCl3.6H2O. It was found that at 30/25 °C (day/night) and photosynthetic photon flux density 1100–1300 μmol m−2 s−1, the chlorotic maize plants recovered for 4 days of iron re-supply. An increase in the fresh and dry weight, leaf area, net
photosynthetic CO2 uptake of maize leaves, leaf pigment composition and chlorophyll fluorescence was more pronounced in the plants supplied
with Fe3+ chelates of polymers bearing 8QOH groups attached at 5-position, compared to the other tested Fe3+complexes. The importance of the stability of Fe3+ complexes, structure of the chelating agent and the necessity of effective ligand exchange between synthetic chelators and
free phytosiderophore in iron uptake by strategy II plants was discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
Iron uptake from two Fe3+-hydroxamate siderophores, ferrioxamine B and Fe3+-rhodotorulate, by iron-stressed Chlorella vulgaris (ATCC strain 11468) was evaluated with some comparison to iron uptake from synthetic and organic acid ferric chelates. Iron-stress induced iron uptake from ferrioxamine B. Dissipation of the electrochemical gradient, via uncouplers, inhibited iron uptake. Respiratory inhibitors gave variable results, an indication that a direct link to respiration was not apparent. Vanadate inhibition of iron uptake indicated that an ATPase or phosphate intermediate could be involved in the uptake mechanism. Divalent cations manifested variable effects dependent on the cation and chelator used. These data confirm that C. vulgaris has an inducible iron-uptake system for Fe3+-hydroxamic acid siderophores which may involve a different mechanism than that observed for other chelates. 相似文献
11.
Summary The chemical equilibrium and E value for Zn was calculated in 9 soils of Haryana (India) which represented mainly entisol
and inceptisols. The rate of isotopic exchange between65Zn and native soil Zn was quite rapid and radioactivity reduced to about 0.2 per cent of initial activity after 3 days but
total Zn concentration in soil solution did not decrease. In 5 out of 9 soils equilibrium was established in 2 to 3 days.
In typic ustochrepts having high clay content (3,4) equilibrium was attained in two days. In typic udipsamments (2), typic
camborthids (8) and aquic vertic ustichrepts (9) it took 3 days to set equilibrium. Typic ustochrepts (5) took 5 days for
equilibrium whereas typic ustipssaments (6) and typic camborthids of high O.C. did not attain equilibrium even in 7 days.
This indicated that the chemistry and availability of Zn in soil would depend on soil types.
When ZnE was estimated by applying activity after equilibrium with carrier Zn and by applying activity with carrier Zn before equilibrium
was set, there was no agreement in ZnE in two methods. Increasing ZnE with increasing Zn dose was observed by both methods only in alkaline typic ustochrept (4). In some soils higher E values
than added amounts were observed, whereas, in soil 8 negative E values were obtained. The E values become erratic and are
over estimated where complex reactions take place due to high pH, high O.C. and high complex forming elements. 相似文献
12.
Paul F. Killian Clifford J. Bruell Chenju Liang Michael C. Marley 《Soil & Sediment Contamination》2007,16(6):523-537
The persulfate anion (S2O8 2?) is a strong oxidant with a redox potential of 2.01 V. However, when mixed with iron (II), it is capable of forming the sulfate radical (SO4 ?.) that has an even higher redox potential (E o = 2.6 V). In these studies the sulfate radical was investigated to determine if it was a feasible oxidant for the destruction of BTEX and PAH compounds found in MGP contaminated soil. The sulfate radical was generated by either the sequential addition of iron (II) solutions or by a single addition of a citric acid chelated iron (II) solution. The sequentially added iron destroyed 86% of the total BTEX concentration and 56% of the total PAH concentration in the soil. The citric acid chelated iron destroyed 95% of the total BTEX concentration and 85% of the total PAH concentration. A second dose of persulfate and citric acid chelated iron (II) resulted in the destruction of 99% of the total BTEX concentration and 92% of the total PAH concentration. In both the sequential and chelated iron studies the lower molecular weight BTEX compounds were oxidized to a greater extent than the higher molecular weight BTEX compounds, whereas the oxidation of PAH compounds showed no preference to molecular weight. 相似文献
13.
Moawad Abdallah Moawad 《Plant and Soil》1971,34(1):619-625
Zusammenfassung Junge Sonnenblumenpflanzen nahmen 8 Std. lang nicht markiertes und danach 15 Std. lang mit Fe59 markiertes Eisen in Form von Fe-Chlorid, Fe-EDTA oder Fe-Citrat auf.
1. Bei allen drei Eisenformen absorbierten die Pflanzenwurzeln mehr Eisen aus der N?hrl?sung mit 0,1 ppm Fe als aus der mit
1,0 ppm Fe.
2. Die Wurzeln der mit Fe-Chlorid ern?hrten Pflanzen enthalten den h?chsten Gehalt an Fe59.
3. Das Stengelexsudat der 0,1 ppm Fe-Reihe enthielt weniger Fe59 als das Exsudat der 1,0 ppm Fe-Reihe.
4. Eine sichere Beziehung zwischen der Ern?hrung mit den verschiedenen drei Eisenformen und der ausgeschiedenen Exsudatmenge
konnte nicht festgestellt werden. Ebenfalls bestand kein Zusammenhang zwischen der ausgeschiedenen Exsudatmenge und ihrem
Fe59-Gehalt.
5. Der Gehalt des Stengelexsudats an Fe59 war bei der Ern?hrung mit Fe-EDTA und Fe-Citrat h?her als bei Fe-Chlorid.
Auszug aus der Dissertation des Verfassers. 相似文献
Relationships between iron uptake and iron transport in plants
Summary The uptake of unlabelled iron for 8 h and of Fe59, given as Fe chloride, Fe EDTA and Fe citrate for 15 h, was investigated in young sunflower plants. 1. In all three iron forms the roots absorbed more iron from the nutrient solution with 0.1 ppm Fe than with 1.0 ppm Fe. 2. The roots of those plants, supplied with Fe-chloride contained the highest amount of Fe59. 3. The stem exudate of plants, given a nutrient solution with 0.1 ppm Fe contained less Fe59 than the exudate of plants, grown in a nutrient solution containing 1.0 ppm Fe. 4. No close relationship between the nutrition with the three iron forms and the produced amount of exudate could be established. Furthermore no correlation between the produced amount of exudate and its Fe59 content could be found. 5. The content of Fe59 in the stem exudate was higher when Fe EDTA and Fe citrate were given as compared with Fe chloride.
Auszug aus der Dissertation des Verfassers. 相似文献
14.
Evidence for a specific uptake system for iron phytosiderophores in roots of grasses 总被引:33,自引:7,他引:26
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Roots of grasses in response to iron deficiency markedly increase the release of chelating substances (`phytosiderophores') which are highly effective in solubilization of sparingly soluble inorganic FeIII compounds by formation of FeIIIphytosiderophores. In barley (Hordeum vulgare L.), the rate of iron uptake from FeIIIphytosiderophores is 100 to 1000 times faster than the rate from synthetic Fe chelates (e.g. Fe ethylenediaminetetraacetate) or microbial Fe siderophores (e.g. ferrichrome). Reduction of FeIII is not involved in the preferential iron uptake from FeIIIphytosiderophores by barley. This is indicated by experiments with varied pH, addition of bicarbonate or of a strong chelator for FeII (e.g. batho-phenanthrolinedisulfonate). The results indicate the existence of a specific uptake system for FeIIIphytosiderophores in roots of barley and all other graminaceous species. In contrast to grasses, cucumber plants (Cucumis sativus L.) take up iron from FeIIIphytosiderophores at rates similar to those from synthetic Fe chelates. Furthermore, under Fe deficiency in cucumber, increased rates of uptake of FeIIIphytosiderophores are based on the same mechanism as for synthetic Fe chelates, namely enhanced FeIII reduction and chelate splitting. Two strategies are evident from the experiments for the acquisition of iron by plants under iron deficiency. Strategy I (in most nongraminaceous species) is characterized by an inducible plasma membrane-bound reductase and enhancement of H+ release. Strategy II (in grasses) is characterized by enhanced release of phytosiderophores and by a highly specific uptake system for FeIIIphytosiderophores. Strategy II seems to have several ecological advantages over Strategy I such as solubilization of sparingly soluble inorganic FeIII compounds in the rhizosphere, and less inhibition by high pH. The principal differences in the two strategies have to be taken into account in screening methods for resistance to `lime chlorosis'. 相似文献
15.
Summary
Geotrichum candidum is capable of utilizing iron from hydroxamate siderophores of different structural classes. The relative rates of iron transport for ferrichrome, ferrichrysin, ferrioxamine B, fusigen, ferrichrome A, rhodotorulic acid, coprogen B, dimerium acid and ferrirhodin were 100%, 98%, 74%, 59%, 49%, 35%, 24%, 12% and 11% respectively. Ferrichrome, ferrichrysine and ferrichrome A inhibited [59Fe]ferrioxamine-B-mediated iron transport by 71%, 68% and 28% respectively when added at equimolar concentrations to the radioactive complex. The inhibitory mechanism of [59Fe]ferrioxamine B uptake by ferrichrome was non-competitive (K
i 2.4 M), suggesting that the two siderophores do not share a common transport system. Uptake of [59Fe]ferrichrome, [59Fe]rhodotorulic acid and [59Fe]fusigen was unaffected by competition with the other two siderophores or with ferrioxamine B. Thus,G. candidum may possess independent transport systems for siderophores of different structural classes. The uptake rates of [14C]ferrioxamine B and67Ga-desferrioxamine B were 30% and 60% respectively, as compared to [59Fe]ferrioxamine B. The specific ferrous chelates, dipyridyl and ferrozine at 6 mM, caused 65% and 35% inhibition of [59Fe]ferrioxamine uptake. From these results we conclude that, although about 70% of the iron is apparently removed from the complex by reduction prior to being transported across the cellular membrane, a significant portion of the chelated ligand may enter the cell intact. The former and latter mechanisms seem not to be mutually exclusive. 相似文献
16.
Kinetics of radioactive iron transport were examined in three strains of Bacillus megaterium. In strain ATCC 19213, which secretes the ferric-chelating secondary hydroxamic acid schizokinen, 59Fe3+ uptake from 59FeCl3 or the ferric hydroxamate Desferal-59Fe3+ was rapid and reached saturation within 3 min. In strain SK11, which does not secrete schizokinen, transport from 59FeCl3 was markedly reduced; the two ferric hydroxamates Desferal-59Fe3+ or schizokinen-59Fe3+ increased both total 59Fe3+ uptake and the 59Fe3+ appearing in a cellular trichloroacetic acid-insoluble fraction, although 10 min was required to reach saturation. Certain characteristics of transport from both ferric hydroxamates and FeCl3 suggest that iron uptake was an active process. The growth-inhibitory effect of aluminum on strain SK11 was probably due to the formation of nonutilizable iron-aluminum complexes which blocked uptake from 59FeCl3. Desferal or schizokinen prevented this blockage. A strain (ARD-1) resistant to the ferric hydroxamate antibiotic A22765 was isolated from strain SK11. Strain ARD-1 failed to grow with Desferal-Fe3+ as an iron source, and it was unable to incorporate 59Fe3+ from this source. Growth and iron uptake in strain ARD-1 were similar to strain SK11 with schizokinen-Fe3+ or the iron salt as sources. It is suggested that the ferric hydroxamates, or the iron they chelate, may be transported by a special system which might be selective for certain ferric hydroxamates. Strain ARD-1 may be unable to recognize both the antibiotic A22765 and the structurally similar chelate Desferal-Fe3+, while retaining its capacity to utilize schizokinen-Fe3+. 相似文献
17.
《Chemical Speciation and Bioavailability》2013,25(3):147-158
AbstractMineral, complex and chelated micronutrient fertilisers are widely used in agriculture. However, there have been few studies on manganese and zinc fertilisers. In fact, specific chelating agents to provide these micronutrients to plants have not been found, in contrast to iron. This work considers the interactions of novel and traditional ligands in micronutrient mixtures used in hydroponics and fertigation. Theoretical speciation studies comparing the stability in solution have been carried out to simulate the possible interactions that can affect Fe, Mn and Zn in aqueous formulations containing these micronutrients. Unknown stability constants of ligands with Zn and Mn have been determined. Also, theoretical speciation investigations in hydroponic conditions have been carried out. It has been found that the new chelating agents, IDHA and EDDS, and the poorly studied o,p-EDDHA, can be good alternatives to the traditional sources such as EDTA, HEEDTA and DTPA principally for Zn fertilisers. The Mn and Zn chelates with o,p-EDDHA and complexes with lignosulfonate and gluconate have also shown high stability in a hydroponic nutrient solution, maintaining more than 80% Mn in solution until pH 10. The presence of o,o-EDDHA/Fe3+ and o,p-EDDHA/Fe3+ enhances the stability of Zn in solution in the mixed fertilisers. More studies with substrates are necessary to confirm these results and to extend them to other agronomic conditions. 相似文献
18.
The plant availability of Fe from synthetic chelates has not been examined extensively for plants having the second strategy in iron uptake. Since these plants also excrete chelating agents, competition between natural and synthetic ligands is expected. This research was conducted to study the efficiency of different iron-chelates (Fe-EDTA, Fe-DTPA, Fe-EDDHA and a commercial product, Rexene) inLolium multiflorum iron nutrition. Plants were grown in a greenhouse with hydroponic culture using a buffered nutrient solution at pH 8. Initial iron concentration in the nutrient solution was near 0.5 mgl–1 and solutions were replaced weekly. In an other Fe-EDTA treatment the same amount of chelate was supplied by four additions during each week.Changes of iron concentration in the nutrient solution, harvestable yield, Fe, Mn, Cu and Zn content in plant tissue and chlorophylllevels in leaves are discussed as parameters to evaluate chelate efficacy. Fe-EDDHA, without inorganic iron in the medium was not as effective as the commercial product Rexene, containing Fe-EDDHA and some extra weakly complex iron, which gave the highest yields. Fe-EDTA applied once a week with fresh nutrient solution was less effective than a four part addition as seen from Chl1/[Fe] ratios. 相似文献
19.
Metal chelates in the storage and transport of neurotransmitters: interactions of metal ions with biogenic amines 总被引:1,自引:1,他引:0
Abstract— Equilibrium studies on the interaction of biogenic amines with iron (Fe2+ and Fe3+) and magnesium (Mg2+) were undertaken in an attempt to correlate the stabilities of metal-amine chelates and the reported granule-binding affinities of the biogenic amines. By means of potentiometric equilibrium measurements at 25°C and an ionic strength of 10 (KNO3) the formation constants of the Fe2+ chelates with norepinephrine (NE) and adenosine-S-triphosphate (ATP) were determined. Possible structures were derived for the co-ordinate binding of Fe2 + with NE. The interactions of Fe2+ and Fe2+-ATP with NE were investigated and the formation of Fe2+-NE-ATP (1:1:1) mixed ligand ternary chelate was proposed on the basis of the equilibrium data. Information obtained from chelation studies of Fe2+ with pyrocatechol and ethanolamine taken together with the data obtained on the Fe2+-NE system indicated that the binding of Fe2+ by NE was probably via the pyrocatechol moiety. Equilibrium constants for the binding of tyramine (TA) dopamine (DA) and NE with Mg2+ were also determined. The equilibrium data obtained on the Mg2+-amine systems indicated a correlation between the metal-amine binding affinities and the structure and amine-release (and storage) activities of the biogenic amines. A consideration of the stabilities of the Fe2+ and Mg2+ chelates together with the occurrence of these metal ions in synaptosomes suggests their possible involvement in the intra vesicular amine-binding and storage sites. 相似文献
20.
Meik Meißner Michael Köhler Luitgard Schwendenmann Dirk Hölscher Jens Dyckmans 《Plant and Soil》2014,376(1-2):327-335