Seeds of Phaseolus vulgaris cv. Limburgs vroege were sown in peat moss supplemented with ZnSO4 (600 mg kg-`) and irrigated with distilled water for 14 days. In the Zn-treated plants, significant reductions were shown in the capacities of glutathione reductase (GR) and ascorbate peroxidase (APOD) in the primary leaves as well as enhancement of the two main antioxidants in roots syringaldazine peroxidase (SPOD) and guaiacol peroxidase (GPOD). Zinc also caused reduced activities of superoxide dismutase (SOD), catalase (CAT) and isocitrate dehydrogenase (ICDH) nearly equally in leaves and roots. The Zn-induced increase in the content of individual amino acids (except cysteine) in primary leaves and roots was associated with a decrease in their total protein content. SDS-PAGE revealed de novo synthesis of possibly a phytochelatin synthase (MM 23.49 kDa) and two Zn-binding metallothionine-like proteins (MM 10.71 and 10.16 kDa) only in the root. These proteins might be responsible for the amelioration of the impact of Zn on the root. Another protein (MM 20.30 kDa) was induced in leaves which might be assumed to interfere with the reduction in enlargement of their cells.