Metal-binding peptides: Their role in responses to metal stress

Journal Article · Sat Apr 01 00:00:00 EST 1989 · Plant Physiology, Supplement; (USA)

OSTI ID:6639069

Rauser, W E ^[1]

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1. Univ. of Guelph, Ontario (Canada)

Excess metals are one stress that plants may encounter. The metals Cd, Cu, Ni, and Zn are considered because of concern for their entry into the foodchain of animals and man. Studies of metal tolerant plants and cell cultures suggest three types of responses: exclusion of metal from protoplasts by binding to cell walls, differential membrane transport reducing metal exposure of enzymes, and intracellular chelation of metal in innocuous forms. One group of compounds involved in the latter response are metal-binding peptides designated phytochelatins. They are a family of small peptides composed of five kinds of amino acids, including 2 to 11 cysteines which provide thiols for selective binding of metal. Metals induce the synthesis of phytochelatins through unknown enzymes involving glutathione. In plant cell cultures the peptides bind about 90% of the intracellular Cd. In roots of young plants up to half of the metal is bound by phytochelatins. Intact plants probably use a combination of responses to deal with excess metals, phytochelatins may dominate in certain cases.

• OSTI ID: 6639069
• Journal Information: Plant Physiology, Supplement; (USA), Vol. 89:4; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CADMIUM
TOXICITY
COPPER
NICKEL
PEPTIDES
BIOLOGICAL FUNCTIONS
ZINC
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL STRESS
CELL WALL
MEMBRANE TRANSPORT
PLANTS
CELL CONSTITUENTS
ELEMENTS
FUNCTIONS
KINETICS
METALS
ORGANIC COMPOUNDS
PROTEINS
REACTION KINETICS
TRANSITION ELEMENTS
560300* - Chemicals Metabolism & Toxicology