Parietaria judaica pollen extract was separated by preparative isoelectric focusing and showed two allergenic components (A1 and A2) heterogeneously distributed within the pH gradient (pH 3-10). By fused-rocket immunoelectrophoresis, A1 was detected from pH 3 to 10, whereas A2 was only found at pH values below 8. Both components, A1 and A2, showed IgE-binding ability throughout their pH ranges, as determined by crossed-radio immunoelectrophoresis. In addition, all the preparative isoelectric focusing fractions contained the main allergenic polypeptide of P. judaica (Pj10) when analyzed by SDS-PAGE. This polypeptide was shown to be a glycopeptide or to be bound to a glycoprotein with alpha-D-mannopyranoside or alpha-D-glycopyranoside residues. Implication of charged sugar residues in the wide distribution of P. judaica allergens in a pH gradient is discussed.