Phytochelatins, a class of heavy-metal-binding peptides from plants, are functionally analogous to metallothioneins

Grill, Erwin; Winnacker, Ernst‐Ludwig; Zenk, Meinhart H.

doi:10.1073/pnas.84.2.439

Cited by 746 publications

(465 citation statements)

References 28 publications

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“…The PCs in control plants may have been produced in response to the Zn 2+ and Cu 2+ in the nutrient solution. Along with Cd 2+ , these metal ions can also induce the synthesis of PCs (Grill et al, 1987). The amounts of PCs synthesized in response to nutrient cations are expected to be low but it was surprising that we detected only PC 4 in plants from control and CdCl 2 treatments.…”

Section: Phytochelatinsmentioning

confidence: 78%

“…Phytochelatins are functionally analogous to metallothioneins (MTs), which are produced by animals and some fungi and have been identified in plants ranging from algae to monocots and dicots (Grill et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…These include the cations antimony (Sb 5+ ), bismuth (Bi 3+ ), cadmium (Cd 2+ ), copper (Cu 2+ ), gold (Au + ), lead (Pb 2+ ), mercury (Hg 2+ ), nickel (Ni 2+ ), silver (Ag + ), tin (Sn 2+ ) and zinc (Zn 2+ ) and the anions arsenate (AsO 4 3-) and selenite (SeO 3 2-) (Grill et al, 1987;1988). Among these, the strongest activation of the enzyme was observed with Cd 2+ .…”

Section: Introductionmentioning

confidence: 99%

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Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Akhter

McGarvey

Macfie

2012

Journal of Plant Physiology

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SummaryCadmium (Cd) is a non-essential trace element and its environmental concentrations are approaching toxic levels, especially in some agricultural soils. Understanding how and where Cd is stored in plants is important for ensuring food safety. In this study, we examined two plant species that differ in the distribution of Cd among roots and leaves. Lettuce and barley were grown in nutrient solution under two conditions: chronic (4 week) exposure to a low, environmentally relevant concentration (1.0 µM) of Cd and acute (1 h) exposure to a high concentration (5.0 mM) of Cd. Seedlings grown in solution containing 1.0 µM CdCl 2 did not show symptoms of toxicity and, at this concentration, 77% of the total Cd was translocated to leaves of lettuce, whereas only 24% of the total Cd was translocated to barley leaves. We tested the hypothesis that differential accumulation of Cd in roots and leaves is related to differential concentrations of phytochelatins (PCs), and its precursor peptides. The amounts of PCs and their precursor peptides in the roots and shoots were measured using HPLC. Each of PC 2-4 was synthesized in the barley root upon chronic exposure to Cd and did not increase further upon acute exposure. In the case of lettuce, no PCs were detected in the root given either Cd treatment.The high amounts of PCs produced in barley root could have contributed to preferential retention of Cd in barley roots.

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Section: Phytochelatinsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Akhter

McGarvey

Macfie

2012

Journal of Plant Physiology

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“…At lower, non-toxic concentrations, the plants might be able to keep control over the AsO 4 3± uptake and the detoxifying mechanisms such as phytochelatin and glutathione synthesis [24], and therefore they might be able to deal with a higher accumulation of As. As [mg/g dry weight] Figure 2.…”

Section: Engmentioning

confidence: 99%

Capacity of Salvinia minima Baker to Tolerate and Accumulate As and Pb

Hoffmann

Kutter

Santamaría³

2004

Engineering in Life Sciences

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The use of Salvinia minima Baker for the removal of lead (Pb) and arsenic (As) from aqueous solutions was investigated. In a first approach, the effect of different concentrations of AsO 4 3± and Pb(II) on the growth and accumulation of these metals was studied. The plants tolerated concentrations of 20±40 lM Pb(II) and 200 lM of AsO 4 3± . Toxic effects occurred when 20 lM of Pb(II) and 100 lM AsO 4 3± were used. These effects included growth inhibition (decreased yield of biomass and frond area) as well as an altered frond (leaf-like structure in ferns) appearance and tissue consistence. S. minima showed a high uptake of Pb (34 mg/g dry weight) compared to As (0.5 mg/g dry weight). The uptake of As was inhibited by phosphate. Additional kinetic studies revealed a two-stage accumulation of both elements: a rapid first phase within the first 6±12 hours and a slow second phase up to the end of the 96-hour experiment.

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“…10000 occur in higher plants.l4-21 However, the apparent molecular weight of MT-like proteins generally (and drastically) depends on the ionic strength of the eluent in gel filtration. 5,22,23 In fact, under the present HPLC-ICP/ MS conditions, commercial MT-I from rabbit liver (Mr 6000 -7000) exhibited a retention time of 690 s, which corresponds (based on our calibration) to a molecular weight of ca. 15000.…”

Section: Detection Limitsmentioning

confidence: 66%

Application of High-Performance Liquid Chromatography/Inductively Coupled Plasma Mass Spectrometry to the Speciation of Cadmium-Binding Metallothionein-like Protein in a Cyanobacterium

Takatera

Watanabe

1992

ANAL. SCI.

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A metal-binding metallothionein-like protein in a cyanobacterium, Anacystis nidulans R-2, has been spectated by highperformance gel permeation liquid chromatography combined with inductively coupled plasma mass spectrometry (HPLC-ICP/ MS). Cadmium-stressed culturing induced a characteristic water-soluble protein in the cyanobacterium. The protein had an apparent molecular weight of ca. 10000, and contained predominantly cadmium as well as smaller amounts of copper and zinc. The cysteine residues in the protein were quantitated on 202Hg chromatograms after modifying the sulfhydryl groups withp-chloromercuribenzoate.The present findings demonstrate that the HPLC-ICP/ MS technique has high potential for the trace level speciation of heavy metal-binding proteins of environmental interest in living organisms. KeywordsInductively coupled plasma mass spectrometry, high-performance liquid chromatography, metallothionein, cyanobacterium, sulfhydril group A number of heavy metals, including copper and zinc, are essential micronutrients in biological systems, though at high levels most heavy metals are toxic.l Heavy metals are now being accumulated in the environment through human activity, including industrial production2, and are becoming a threat to the sound development of the biosphere. To assess the impact on elemental distribution in the environment from heavy metals, it is necessary to correctly evaluate their uptake by, and the effects on, living organisms. Cyanobacteria constitute a class of organisms which are most relevant and most important in this respect, since they are, as accumulators of heavy metals, the primary food to enter trophic chains in the aquatic system. Thiol-rich metal binding proteins, generally called metallothioneins (MTs), are known to participate in the metal homeostasis and detoxification in animals.3 MTs bind Cd, Cu, and Zn ions through cysteine residues. Similar compounds have been isolated from eukaryotic organisms, usually as Cd-thionein-like substances.3 The MTs in cyanobacteria, to our knowledge, have been studied only by Olafson and coworkers4, who determined the amino acid sequence of an MT.Detection and quantitation of MTs have commonly been carried out via metal analysis using atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission spectrometry (ICP/ AES). In these procedures, one has to assume a metal/ protein stoichiometry and, moreover, can obtain only an approximate value of the MT content if plural kinds of metals are contained in a molecule. In order to alleviate such problems, the SH content in MTs was measured by differential pulse polarography4(a) or color developments However, to obtain a reliable value, the standards must be identical with the protein to be quantitated and, when necessary, steps to remove interfering substances are needed before assaying.The recently developed inductively coupled plasma mass spectrometry (ICP/ MS) features highly sensitive, metal-specific analysis of metalloproteins without the need to use radioactive tracer...

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Phytochelatins, a class of heavy-metal-binding peptides from plants, are functionally analogous to metallothioneins

Cited by 746 publications

References 28 publications

Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors

Capacity of Salvinia minima Baker to Tolerate and Accumulate As and Pb

Application of High-Performance Liquid Chromatography/Inductively Coupled Plasma Mass Spectrometry to the Speciation of Cadmium-Binding Metallothionein-like Protein in a Cyanobacterium

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