Phytochelatins metal complexes

Grill, E., Winnacker, E.-L. Zenk, M.H. (1985). Phytochelatins The principal heavy-metal complexing peptides of higher plants. Science, 230, 674-6. 

The coccolithophore E. huxleyi releases a variety of thiols into the external medium upon exposure to elevated Cd concentrations [90]. Cys and GSH were the primary thiols released by cells exposed to Cd only, whereas y-Glu-Cys was the primary thiol when Cu and Zn were also present at high concentrations. Like phytochelatins, these low molecular weight thiols released by phytoplankton may also serve as organic metal-complexing agents in surface seawater. 

Robbins, A.H. and Stout, C.D. (1992) Metallothioneins Synthesis, Structure and Properhes of Metallothioneins, Phytochelatins, and Metal-Thiolate Complexes (eds M.l. ShDman, C.F. Shawlll and KT. Suzuki), VCH Publishers, Weinheim, pp. 31—54. 

Nickel is localized predominantly in the epidermal and subepidermal of the leaves. However, in leaves of some hyperaccumulator plants such as T. caerulescens and T. goesingense, Ni and Zn are found mainly in vacuoles (Salt and Kramer, 2000). Trace elements also are inactivated in the vacuoles as high-affinity low-molecular-weight metal chelators (such as Cd-phytochelatin complex), providing plants with trace element tolerance. Some Ni in leaves is found to be associated with cell wall pectates as well. 

Stillman MJ, Shaw CF III, Suzuki KT (1992) Metallothioneins. Synthesis, structure, and properties of metallothioneins, phytochelatins and metal-thiolate complexes. VCH Publishers, New York Stratford IJ, Hoe S, Adams GE, Hardy C, Williamson C (1983) Abnormal radiosensitizing and cytotoxic properties of ortho-substituted nitroimidazoles. Int J Radiat Biol 43 31-43 Stubbe J, Kozarich JW (1987) Mechanisms of bleomycin-induced DNA degradation. Chem Rev 87 1107-1136... 

Some of the dominant functional groups of organic matter that commonly form strong complexes, albeit at a slow rate, with trace metals are -COOH, -OH, -NR2, and -SR2 (R = -CH2 or -H). Some natural sources containing these functional groups are phytochelatins (siderophores), biopolymers (e.g., proteins), and humic substances. 

M. J. Stilhnan, C. F. Shaw 111, and K. T. Suzuki eds, Metallothioneins Synthesis, Structure, and Properties of Metallothioneins, Phytochelatins and Metal-thiolate Complexes , VCH, New York, 1992. 

Phytochelatins [ y-Glu-Cys) -Gly], PC , may be induced by a variety of heavy metals in vivo and in vitro. The response is complex and varies with each system of study. It is certain, however, that Cd2+ is by far the strongest inducer of PC synthesis and is the... 

---