Characterization of a Cadmium-Binding Complex of Cabbage Leaves
Open Access
- 1 November 1984
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 76 (3), 797-805
- https://doi.org/10.1104/pp.76.3.797
Abstract
The chemical nature of a principal, inducible cadmium-binding complex which accumulates in cabbage leaves (Wagner and Trotter 1982 Plant Physiol 69: 804-809) was studied and compared with that of animal metallothionein and copper-binding proteins isolated from various organisms. The apparent molecular weight of native cabbage complex and carboxymethylated ligand of the complex under native conditions as determined by gel filtration was about 10,000 daltons. Under denaturing conditions their apparent molecular weights were about 2000 daltons. Ligand of native complex contained 37, 28, and 9 residue per cent of glutamic acid-glutamine, cysteine, and glycine, respectively, and low aromatic residue, serine and lysine content. The high acidic and low hydrophobic residue content explain the behavior of complex on electrophoresis in the presence and absence of sodium dodecyl sulfate. Its isoelectric point was below 4.0 and it bound 4 to 6 moles cadmium per mole ligand in what appear to be cadmium-mercaptide chromophores. The complex was found to be heat stable, relatively protease insensitive, and lacking in disulfide bonds. Attempts to determine the primary sequence of reduced native complex and carboxymethylated, cleaved ligand using the Edman degradation procedure were unsuccessful. An electrophoretic procedure is described for preparative isolation of purified complex and a method is described for monitoring ligand of complex as its fluorescent dibromobimane adduct.Keywords
This publication has 20 references indexed in Scilit:
- Functions of metallothioneinBiochemical Pharmacology, 1982
- Cadmium Distribution and Chemical Fate in Soybean PlantsPlant Physiology, 1981
- Isolation of copper thionein from rat liverArchives of Biochemistry and Biophysics, 1981
- Partial Characterization of a Cadmium-binding Protein from the Roots of Cadmium-treated TomatoPlant Physiology, 1980
- Copper metallothionein, a copper-binding protein from Neurospora crassaNature, 1980
- Subcellular Distribution and Chemical Form of Cadmium in Bean PlantsPlant Physiology, 1980
- Metallothioneins and their role in the metabolism and toxicity of metalsLife Sciences, 1978
- Taipoxin, an Extremely Potent Presynaptic Neurotoxin from the Venom of the Australian Snake Taipan (Oxyuranus s. scutellatus)JBIC Journal of Biological Inorganic Chemistry, 1976
- Isoelectric focusing in polyacrylamide gelsBiochimica et Biophysica Acta (BBA) - Protein Structure, 1971
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970