Penicillin acylase purification and storage stabilization in the presence of water-soluble polymers were studied. Eleven synthetic polymers were evaluated in this survey. It was shown that protein suspension stabilization, precipitation, and enzyme denaturation were affected by both protein and polymer concentration and mostly depended on the particular polymer-enzyme system. The possibility of acylase purification was also described. Fivefold purification was reached if 30% sulfomethylated poly(acrylamide) in 0.1 wt. % concentration was used. Six of eleven polymers significantly increased enzyme stability for storage at 37 degrees C, whereas three of them offered the purification effect. They were selected for future investigation.