Metal-binding proteins in bream (Abramis brama L.) caught in the River Elbe

Metal-binding proteins were investigated in livers of bream caught in the River Elbe from Steti (Czech Republic) to Hamburg (Federal Republic of Germany). A major zinc and copper binding protein fraction with a low molecular weight of 10 000 to 12 000 Da and with properties similar to mammalian hepatic metallothionein was isolated from bream livers using gel filtration chromatography. Two protein isoforms could be separated by reversed phase-high performance liquid chromatography (RP-HPLC), however, mercury was associated with only one isoform. The possibility of different detoxification potentials of the isoforms is discussed. Maximal concentrations of metal-binding protein were detected in samples from Dresden. If metal-binding proteins are to be included in a biological monitoring study, further investigations are required.