Synthetic phytochelatins (ECs) are a new class of metal-binding peptides with a repetitive metal-binding motif, (Glu-Cys)(n)Gly, which were shown to bind heavy metals more effectively than metallothioneins. However, the limited uptake across the cell membrane is often the rate-limiting factor for the intracellular bioaccumulation of heavy metals by genetically engineered organisms expressing th...

Increasing emissions of heavy metals such as cadmium, mercury, and arsenic into the environment pose an acute problem for all organisms. Considerations of the biochemical basis of heavy metal detoxification in animals have focused exclusively on two classes of peptides, the thiol tripeptide, glutathione (GSH, gamma-Glu-Cys-Gly), and a diverse family of cysteine-rich low molecular weight protein...

Phytochelatins (PCs) are metal-binding cysteine-rich peptides, enzymatically synthesized in plants and yeasts from glutathione in response to heavy metal stress by PC synthase (EC 2.3.2.15). In an attempt to increase the ability of bacterial cells to accumulate heavy metals, the Arabidopsis thaliana gene encoding PC synthase (AtPCS) was expressed in Escherichia coli. A marked accumulation of PC...

Phytochelatin synthases (PCS) mediate cellular heavy-metal resistance in plants, fungi, and worms. However, phytochelatins (PCs) are generally considered to function as intracellular heavy-metal detoxification mechanisms, and whether long-distance transport of PCs occurs during heavy-metal detoxification remains unknown. Here, wheat TaPCS1 cDNA expression was either targeted to Arabidopsis root...

Three-week-old alfalfa (Medicago sativa), barley (Hordeum vulgare) and maize (Zea mays) were exposed for 7 d to 30 µm of mercury (HgCl(2) ) to characterize the Hg speciation in root, with no symptoms of being poisoned. The largest pool (99%) was associated with the particulate fraction, whereas the soluble fraction (SF) accounted for a minor proportion (<1%). Liquid chromatography coupled with ...

Chromium (Cr) is a non-biodegradable heavy metal that persists long in aquatic and terrestrial ecosystems enters the food chain. It cytotoxic even at low concentrations reduces yield of plants. Plants also have cellular mechanisms to manage accumulation ions inside cell diminish possible injury from non-essential ions. This paper reviews current information on plant response Cr, key environment...