Isolation and characterization of a metallothionein-like protein from monkey brain.
A cadmium-binding protein from monkey brain has been isolated, purified and characterized. The absorption spectrum of this protein indicates the presence of Cu-Zn thionein in the normal monkey brain which has a strong affinity to bind cadmium. On cadmium exposure the protein sequestered most of the cadmium which entered the brain. The apparent molecular weight of this protein as determined on a gel filtration column calibrated with marker proteins has been found to be in the range of 11,500-12,000 Da. The ratio of absorbance at 254 nm/280 nm is more than 1 indicating the presence of cadmium-mercaptide bonds, which was further confirmed by the presence of 15 cysteine residues. Polyacrylamide gel electrophoresis of the protein shows 3 bands indicating the presence of 3 isometallothionein forms. Unlike hepatic or renal thioneins, the cadmium-binding protein in brain is not inducible following administration of cadmium. However, when antibodies raised against hepatic metallothionein were cross-reacted with brain Cd-binding protein, a line of identity was observed, indicating the 2 proteins are immunologically identical and share a high degree of structural similarity.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D002104:Cadmium / Q000378:metabolism*; D019256:Cadmium Chloride; D002850:Chromatography, Gel; D003300:Copper / Q000032:analysis; D008253:Macaca mulatta; D008297:Male; D008668:Metallothionein / Q000032:analysis / Q000378:metabolism*; D015032:Zinc / Q000032:analysis
C004203:cadmium-binding protein; D002104:Cadmium; D003300:Copper; D008668:Metallothionein; D015032:Zinc; D019256:Cadmium Chloride