Concanavalin A (Con A) immobilized poly(2-hydroxyethyl methacrylate) (PHEMA) beads were investigated for specific adsorption of yeast invertase from aqueous solutions. PHEMA beads were prepared by a suspension polymerization technique with an average size of 150-200 mum, and activated by epichlorohydrin. Con A was then immobilized by covalent binding onto these beads. The maximum Con A immobilization was found to be 10 mg/g. The invertase-loading capability of the PHEMA/Con A beads was observed at pH 5.0. The values of the Michaelis constant K-m of invertase were significanly larger upon adsorption, indicating decreased smaller for the adsorbed invertase. Adsorption improved the pH stability of the enzyme activity was found to be quite stable in repeated experiments.