Dry oak leaves exhibit the property of accumulating metals when exposed to atmospheric pollution and thus can be used as bioindicators of metal pollution. In this paper the role of proteins, one of the components of leaves involved in the metal fixation, has been investigated. Proteins and protein-metal complexes were extracted purified, separated and concentrated by means of ion exchange chromatography and electophoresis. The results revealed that three different types of proteins having different molecular weights are responsible for metal fixation.