Abstract: Immobilized aminoacylase having high specific activity is obtained by covalent bonding of aminoacylase to a partially hydrolyzed Akrilex P type acrylamide-N,N.sup.1 -methylene-bis (acrylamide) copolymer. Covalent bonding is carried out by partially hydrolyzing the copolymer with a base or an acid to form carboxy groups, activating the carboxy groups with a carbodiimide and coupling aminoacylase to the activated carboxy groups. The aminoacylase may be isolated from mammal kidneys by forming an aqueous kidney extract, heat treating the extract and isolating aminoacylase from the heat treated extract.

Abstract: Aminoacylase is isolated from mammal kidneys by comminuting and homogenizing mammal kidney in water, centrifuging to form an aqueous extract, heating the aqueous extract at 60.degree. to 80.degree. C. for 5 to 15 minutes, centrifuging, adding a salt such as ammonium sulfate to the resultant supernatant, centrifuging to separate solids, dissolving the solids in water, dialyzing and recovering active aminoacylase from the dialyzed solution. The process produces aminoacylase with high specific activity and the process requires fewer purification steps. The aminoacylase obtained may be utilized directly without any subsequent purification to produce immonobilized aminoacylase. Immobilization can be carried out by covalent bonding of the aminoacylase to a partially hydrolyzed Akrilex P type acryl amide-N,N'-methylene-bis(arylamide) copolymer. The recovered aminoacylase can be subjected to two chromatographic purification steps to produce a very pure aminoacylase.