Phytochelatins, a class of heavy-metal-binding peptides from plants, are functionally analogous to metallothioneins
AUTOR(ES)
Grill, Erwin
RESUMO
Phytochelatins are a class of heavy-metal-binding peptides previously isolated from cell suspension cultures of several dicotyledonous and monocotyledonous plants. These peptides consist of repetitive γ-glutamylcysteine units with a carboxyl-terminal glycine and range from 5 to 17 amino acids in length. In the present paper we show that all plants tested synthesized phytochelatins upon exposure to heavy metal ions. No evidence for the occurrence of metallothionein-like proteins was found. All data so far obtained indicate that phytochelatins are involved in detoxification and homeostasis of heavy metals in plants and thus serve functions analogous to those of metallothioneins in animals and some fungi. Phytochelatins are induced by a wide range of metal anions and cations. Phytochelatin synthesis in suspension cultures was inhibited by buthionine sulfoximine, a specific inhibitor of γ-glutamylcysteine synthetase (EC 6.3.2.2). This finding and kinetic studies of phytochelatin induction point to a synthesis from glutathione or its precursor, γ-glutamylcysteine, in a sequential manner, thereby generating the set of homologous peptides.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=304223Documentos Relacionados
- Phytochelatins, the heavy-metal-binding peptides of plants, are synthesized from glutathione by a specific γ-glutamylcysteine dipeptidyl transpeptidase (phytochelatin synthase)
- Hydroxymethyl-phytochelatins [(gamma-glutamylcysteine)n-serine] are metal-induced peptides of the Poaceae.
- Enhanced Bioaccumulation of Heavy Metal Ions by Bacterial Cells Due to Surface Display of Short Metal Binding Peptides
- Metal-specific synthesis of two metallothioneins and gamma-glutamyl peptides in Candida glabrata.
- Non-p53 p53RE binding protein, a human transcription factor functionally analogous to P53